When Sarno gives Longbaugh one last chance to give up his hostage, he opens his wallet and shows it to Longbaugh, but we don't see what he's showing. In the end, we learn that Sarno is Robin's father, so he was apparently showing Longbaugh a wallet family photo of her as a way of saying that he'd stop at nothing to get her back. This is why Parker and Longbaugh know that Sarno, Robin and her child are "family" at the end.
The firearms used by the main cast appear to reflect their characters and upbringing. Joe Sarno and his crew make use of revolvers, projecting an antiquated but reliable and lethal image. Parker and Longbaugh utilize 1911s, reflecting the 80s-style "Modern Technique of the Pistol" and their possible military background. Jeffers utilizes a Heckler and Koch USP, at the time one of the most technologically-advanced handguns on the market, to reflect his polished appearance and highly-paid bodyguard position.
The odd choice of a Gali in 7.62mm and the decision to bring only two magazines can be simply rationalized as it was the only weapon of its kind they could find on the black market (i.e. untraceable), and it only came with two magazines.
