While the Young Guns franchise was based off a well-known and fairly well-documented time period (the Lincoln County War and the intervening years afterwards), the film greatly exaggerates certain situations and character connections. More than one major media outlet
has pointed out how the films frequently disregard historical accuracy for the sake of Rule of Cool, particularly on the part of series screenwriter John Fusco.
- Young Guns:
- Not only were there more Regulators operating during the Lincoln County War (approx. 15, as opposed to the six main characters seen in the film), but most of them were much older, in their 30s or 40s. The characters were deliberately aged down in order to accommodate several Brat Pack stars of the 80s. Conversely, John Tunstall (played by Terence Stamp) was far younger than his film incarnation, dying at the age of 24 (and not on the morning of New Year's Day, 1878, as the film suggests, but on Feb. 24, 1878, in the evening).
- There is enough historical evidence to suggest that Tunstall was not quite the virtuous rancher with a penchant for helping wayward young men, but a Wolf in Sheep's Clothing who was planning to monopolize the local area and bilk the locals out of half their income, as noted in real letters written to his family in England. Conversely, James Dolan (a character who is technically still in the film — in a Freeze-Frame Bonus — but merely shown to be a lackey of Murphy`s) has been largely credite by records as the mastermind that ignited the Lincoln County War, due to the fact that Lawrence Murphy was dealing with terminal cancer at the time, and was in no position to lead the attacks against Tunstall. There is also no known historical evidence that Tunstall spent time educating and civilizing the "Regulators" under his command.
- The subplot regarding Doc Spurlock's budding romance with Yen Sun, a Chinese immigrant who was forcibly taken as Murphy's mistress and later falls in love with Doc (risking her life to stay with him during the ending siege) is completely fabricated for the film, though the situation could be seen as an apocryphal view of the (very real) prostitution of young Chinese girls in the era the film takes place. In real life, Doc was married to a Hispanic woman, Maria (Antonia) Herrera, before the war started, and there is no known historical evidence that Murphy (who, as noted above, was dying of cancer at the time the film takes place) ever had a mistress working for him.
- At the New Year's Eve party in 1878, Billy meets Pat Garrett, and fawns over the latter while saying he wants to be a famous gunslinger like him. While there's competing accounts of whether Pat and Billy knew of/respected each other enough before Billy's death, one thing historians generally agree on is that the two only met for the first time after the Lincoln County War. Additionally, Billy would likely have been far more famous at that time than Garrett, who was a wrangler/bartender with little public awareness. Garrett's reputation wouldn't be cemented until after he killed Billy.
- Andrew "Buckshot" Roberts is depicted as a bounty hunter determined to hunt down the regulators singlehandedly. In real life, Roberts was actually hunted down by the regulators due to his involvement with the Murphy-Dolan faction, and was mortally wounded by them after a long shootout at Blazer's Mill. However, his surprising effectiveness against them as shown in the movie was accurate, as he did in fact single-handedly wound several regulators, kill Dick Brewer, and force the regulators to flee before dying from his wounds the following day.
- The rivalry between Billy (Emilio Estevez) and Dick Brewer (Charlie Sheen) is played up as being a competition for leadership of the gang, with the matter only being dropped when Dick is ambushed and killed by Buckshot Roberts. In actuality, Brewer was considered the leader of the Regulators and no one talked ill of him, with historical reports even suggesting that the Lincoln County War would have ended far differently if he had survived the ambush (with even Billy having no real interest in being the leader, according to known reports). In the film, Brewer is shot and killed with several shots to the chest by Roberts, while in real-life, he was shot between the eyes when he raised his head from behind a pile of logs. Conversely, Roberts wasn't shot several times in an outhouse and then not confirmed dead due to the Regulators being forced to run away, but pursued the Regulators until he was mortally wounded and couldn't run anymore, with even Billy admitting in an historical account that Roberts "licked our crowd to the finish".
- Billy instigating the shootout with Henry Hill was completely fabricated for the film. In reality, Hill (known as Tom, not Henry) was shot and killed while trying to rob a camp with sheep, alongside another robber named Jessie Evans.
- Before the final battle gets underway, Billy considers having Doc write a letter of surrender to the Governor of New Mexico, Axtell, before changing his mind and telling Doc to end the letter by telling Axtell to "kiss (my) ass". There is no indication that such a scenario happened at that specific time, though a formal letter of surrender was eventually written by Billy... to Governor Lew Wallace, a scenario that is shown in the sequel.
- The ending siege at Alexander McSween's property is largely truncated for the film, showing the lead characters (and Sun Yen) holding out for two days against a wave of forces sent by Murphy. The actual sequence of events was both far longer (lasting five days), but involved more than twice the number of Regulators — all of whom were Adapted Out of the film — and several dozen Mexican supporters who aided them. The climax is also completely fabricated — many of the Regulators waited until night to escape and fled through a back entrance to a nearby river, not stormed out and performed a Last Stand, nor did Billy get tossed in a trunk out of a window to ambush the attackers.
- In real life, Alexander McSween died in the middle of a furious shootout, while the movie shows him being gunned down by US army soldiers in front of his house (ostensibly for mildly cheering on the Regulators) at a time when there was no other shooting by anyone.
- In the film, Charlie Bowdre is shot several times while killing his attacker in front of the McSween house, while "Dirty" Steve is gunned down just before managing to escape on the horses Chavez brings. Bowdre's death is an adaptation of a real-life incident where he killed "Buckshot" Roberts in an altercation that caused the latter to shoot a bullet that bounced off Bowdre's belt buckle — and while Bowdre was present at the McSween siege, he escaped unhurt. (Bowdre would be killed at Stinking Springs — a scenario discussed below.) Historical data also suggests that "Dirty" Steve survived the war, and is rumored to have moved to Denver to live out his life under an assumed identity.
- Lawrence Murphy was not present at the actual final battle of the Lincoln County War, nor was he shot by Billy as the movie depicted. In fact, he was in extremely poor health at the time, and died of cancer a few months later.
- The ending text crawl states that Doc went to New York with Sun Yen and lived there until his death, working as a teacher, and Chavez went to California to be a fruit picker until his death. In actuality, Doc went to Texas and lived peacefully for several decades before dying in July 1929, while Chavez remained in New Mexico until his death in July 1923.
- Also in the ending, Billy's headstone in Fort Sumner is said to have had the word "Pals" scrawled on it by an unknown party. Besides the fact that the exact location of Billy's grave was questionable at best within the Fort, it was washed away during the Pecos flood in 1904. The "Pals" gravestone was funded by Billy's surviving associates in 1932, and unlike the film's telling of events, it included Billy, Charlie and Tom Follard's (the latter of whom is only introduced in the sequel) names on the gravestone, along with the word "Pals" etched on it.
- Young Guns II:
- The Framing Device of an aged cowboy named "Brushy" Bill Roberts meeting with a lawyer and offering to turn himself in (identifying himself as Billy) and asking for a pardon from the Governor of New Mexico is played up as if Roberts is Billy, with Estevez playing the aged Roberts and the lawyer seemingly recognizing the latter as Billy (to the point of calling him by his actual name after hearing his story). The real-life accounts are far more murky. Besides the fact that there is, decades on, significant confusion and urban legends by some historians claiming that Roberts was indisputably Billy, the known historical records of Roberts' birthdate would have had him as a baby during the time when Billy was said to be operating. The verifiable evidence includes census data and his family's Bible, indicating Roberts was only about 2 years old at the time Billy the Kid died. The film's epilogue does accurately state that he was discredited, but posits it as a failure of the state (being that it also claims several associates of Billy ID'd him as the correct person, which is not entirely correct, as several witnesses were discredited due to inconsistent testimony), as opposed to an evidence-based decision.
- "William Henry French" (played by Alan Ruck) is a composite of two real-life members of the Regulators (Jim French and Henry Brown), though he bears little resemblance to either one of them (particularly because neither one was cowardly or timid — this appears to have been done to play up Ruck's Typecasting as the same character in previous films he worked on) and is named "Hendry French" in the film itself.
- Tom Folliard is depicted as a young teen from Pennsylvania who joins Billy's gang due to being star-struck with him. In real life, Tom Folliard was from Texas (and did not have the "O" before his last name, as the film claims). He was close to the same age as Billy, he joined the Regulators during the events of the Lincoln County War, and he was in his early 20s when he was killed by Pat Garrett.
- The introductory 1881 sequence of Billy, Garrett and Dave Rudabaugh ambushing a group of bounty hunters who seemingly get the drop on them is unlikely to have ever happened. Besides the fact that Billy and Garrett have a big-little brother kind of friendship (which is... highly unlikely, given that they likely would have met for the first time in 1880, and there is no known historical data suggesting they were close friends), it's more than likely the film played up this connection to make the ending more dramatic. Additionally, Billy is shot in the thigh as Garrett saves him from the remaining bounty hunter — which also never happened, as the only time Billy was shot in the thigh, by his own account and historical date, was during an incident where he shot Sheriff William Brady during the Lincoln County War in 1878.
- The deal between Billy and Governor Lew Wallace is greatle condensed and changed from its real-life equivalent. In the film, Wallace reaches out to Billy and offers to pardon him if he testifies against Lawrence Murphy's surviving men in court, and only if Billy leaves New Mexico for good — but Billy gets sold out to the District Attorney, who has him arrested, put in chains, and told that he has no plans on making Billy testify because he wants to see him hang, leading him to escape custody. In reality, Billy approached Wallace first to have his charges dropped, was promised a pardon if he testified against Murphy's men over what happened at Alexander McSween's property, and submitted to a fake arrest. Billy held up his end of the deal, testifying in court regarding Murphy's men and the rustling trade, but Wallace backs out on his end of the deal, prompting Billy to escape when he learned the D.A. was going to put him on trial for murder.
- The entire sequence of Billy, Garrett and Dave rescuing Doc and Chavez from an underground prison in the town of Lincoln County was fabricated for the film, in order to get the latter characters back into the plot. Conversely, Sheriff Kimbrell did not resign from his post, but elected to run again for sheriff (and subsequently lost to Pat Garrett).
- Garrett accepts a meeting with several people, including Wallace, rancher John Chisum and the D.A., and informed that he will be made the new Sheriff of Lincoln County and given $500 upfront (with a further $500 if he completes the job) to hunt down and kill Billy. In reality, Garrett was Kimbrell's deputy at that time (having won the job after an election), but wouldn't be officially installed as the new Sheriff until Jan. 1, 1881, and he was given a false appointment as a U.S. Marshall to go after Billy. When he arrested Billy on Dec. 23, 1880, Garrett was stiffed on the reward money he was promised by Wallace.
- Jane Greathouse is a prostitute who runs a brothel in White Oaks. The real-life individual her character is based on, Jim Greathouse, was the owner of a station house that operated 50 miles outside of White Oaks.
- One of the motivating factors for why Billy's gang loses trust in each other is the death of Folliard, who is shown in the film to be sent by Billy as a decoy against Garrett's posse, leading Tom to be gunned down by them (and Garrett feeling extreme remorse over killing a boy). In real life, Folliard was killed at night in Fort Sumner, which is hundreds of miles away from the New Mexico border, Folliard didn't instantly die from his wounds, and Garrett was unrepentent over the situation.
- Doc Spurlock performs a Heroic Sacrifice to help the rest of the gang escape Garrett's ambush at Stinking Springs. In reality, Doc was never present after separating from Billy and the other Regulators at the end of the Lincoln County War, and was living a comfortable existence in Texas (not New York, as the film depicts, when he's arrested). This example at least has some explanation, as Kiefer Sutherland asked to have his character killed off due to apparent scheduling conflicts, despite the wishes of screenwriter John Fusco, who eventually acquiesced to the request. Conversely, Chavez was not present at Stinking Springs, and his entire storyline of being fatally wounded (and later succumbing to his wounds after travelling to Fort Sumner and getting one last conversation with Billy) was fabricated for the film. Hendry (Henry French) was also not riding with Billy's gang at the time the Battle of Stinking Springs occurred, either.
- The film shows Dave Rudabaugh escaping to Mexico after the Battle of Stinking Springs, with a pair of individuals he meets at the border unsheathing their blades as he praises his good fortune. The epilogue crawl then shows the statement, "Arkansas Dave Rudabaugh was beheaded shortly after arriving in Mexico as a warning to outlaws crossing the border." In real life, the known historical data suggests that Dave Rudabaugh did not die until five years after the death of Billy the Kid. On February 16th, 1886, Rudabaugh got into a shootout at a saloon during an argument over a card game. After shooting three people (killing two), Rudabaugh was shot multiple times and then decapitated with a machete.
- The interaction between the judge and Billy where the latter is sentenced to death (with the judge saying he's going to "be hanged until you are dead, dead, dead!" and Billy responding with, "You can go to hell, hell, HELL!") was exaggerated for the film. The real Billy was sulking in court when the verdict was read and remained near-silent (only replying 'no' when asked if he had anything to say), while the judge's actual quote was that Billy would be "hang(ed) until your body be dead."
- The circumstances of Billy's jailbreak and escape from town are played up from the real version of events. In the film, Jane (again, a fictional Gender Swap equivalent of a station owner who was nowhere near Billy or the town in reality) slips him the gun at the outhouse, and Billy uses it to get the drop on Deputy Bell and hold him up. The known account from Billy himself states that he never got a gun from the outhouse, instead slipping his hand out of one of the handcuffs and hitting the deputy over the head, before stealing his weapon and shooting him as the latter ran to get help.
- The ending shows Garrett get the drop on Billy by waiting for him in the room of Pete Maxwell (a land baron, who was Adapted Out of the film) in Fort Sumner. The two have a conversation and Billy turns his back on Garrett, going for the door while daring Garrett to shoot him (and it being implied that he allowed Billy to go free, strolling out of the room casually afterwards. In the actual sequence of events (and by his own admission), Garrett did not make his presence known and shot Billy without any hesitation before running out of the building.
