Throughout, there's the discussion of whether or not Lorne Michaels'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 is credited as Rosie Michaels.
As the show goes live, it shows John Belushi coming into frame 39 seconds late through a door. In reality he came on immediately.
Comedienne Valri Bromfield is a blonde, however in the film, the actress portraying her (Corinne Britti) is a redhead.
In one scene, bricks are brought up to Studio 8H via freight elevator. Famously, the real 30 Rock has no freight elevator. Sets/props/costumes for the show arrive by passenger elevator.
The modern subway train edited into the scene where Lorne stands outside 30 Rock before airtime did not exist in 1975.