As the show goes live they have John Belushi coming into frame 39 seconds late through a door. In reality he came on immediately.
Throughout the movie, there's the discussion of whether or not Lorne's wife, Rosie, will be credited with her last name as Shuster or Michaels. In the film, she chooses Shuster, but in the actual episode of "Saturday Night Live", she's created as Rosie Michaels.
Comedienne Valri Bromfield is a blonde, however in the film, the actress portraying her (Corinne Britti) is a redhead.
Although it is stated a few times in the move, and many people have since claimed it, in reality George Carlin was not the first host of Saturday Night. The first episode had no host. Carlin simply provided a few short sets of standup material and did not introduce any sketches, musical acts, or guests. Nor did he host the "Goodnights". The first time SNL had an official host was in episode 2.