At one point prior to launch in the rain, the crew gets a "go" for launch. The Blue Connector on the hose connecting to Gordon's suit is disconnected and the end is up by his name tape on the suit.
Between liftoff and the lightning strike, the neck ring on Al Bean's helmet is unlocked. After staging and fuel cell reset, it is back in the locked position.
After Alan Bean and Dick Gordon say goodbye to one another, they close each hatch (CSM and LM) and it is implied that they simply undocked from one another. This is false as the Apollo spacecraft utilized a docking probe inside the docking tunnel that had to be disassembled before gaining entry to the LM. Thus, this had to be reassembled before the LM could be separated again.
When Al Bean raises his outer reflective sun visor for a photograph, he also raises the inner visor. In actual moonwalks, this second inner visor would always be left down, as it protected the inner pressure helmet from micro-meteoroid impacts, and the wearer's face from UV rays.
While in quarantine at the Lunar Receiving Lab, Dick Gordon mentions wanting to "go to Pe-Te's, for some Cajun food and a couple of beers". The Apollo 12 mission took place in November of 1969. Pe-Te's Cajun Barbecue House, while indeed a popular spot for astronauts, did not open until nearly 10 years later, in the summer of 1979.
IRL Pete Conrad had a prominent gap between his teeth. Al Bean did not. IRL Dave Foley has had (at times) a gap between his teeth. He plays Al Bean...and they seem to accentuate the gap, mistakenly giving it to the wrong astronaut.