Because he was so good as Darby Crash, Shane West was hired as the new vocalist when The Germs decided to reunite for a tour (featuring the other original members: Pat Smear, Lorna Doom, and Don Bolles).
The band playing before The Germs is most likely meant to be Black Flag, as they are playing their song "Police Story".
In the film, Don Bolles is seen as joining the band in September 1977. In reality, Cliff Hanger was the band's drummer at this time, and Don did not join the band until several months later in early 1978.
In the scene at The Whisky, the gig is seen as becoming a full on riot without The Germs even playing a song, when in actuality, The Germs did indeed play a full set that night, as evidenced in the "Caught In My Eye" home video. The date of the show in the movie was also incorrect, being labeled as having taken place on December 23, 1979. In truth, the show took place a day earlier, as presented on a flyer of the event.