Fanservice: Pebbles and Bamm-Bamm both grew up quite nicely. See the beach part of the later opening.
Hilarious in Hindsight: When Pebbles is mayor, she appoints Fred and Barney as police officers. They would be cops years later in another sequel series.
In one of the Season Two episodes where Moonrock invents a "Suitor Computer", Fred muses how kids 'today' will let a computer run their whole lives...back in 1973. Years before technology addiction and online dating sites were ever a thing.