Continuity mistake: In the scene where Drew and his band are setting up on stage, just about to do "Heaven", you can see the Mic has the decorations on it. Then just before Lonny goes to put them on they magically disappear.
Factual error: When Sherrie and Drew are in Tower Records, the background song is I Remember You by Skid Row. But that album wasn't released until 1989, and the movie is set in 1987.
Suggested correction: The movie also says that Drew wrote "Don't Stop Believin" when the song came out in 1981. They also sing Heaven and More than words which didn't come out until 1989 and 1990 respectively. It's a musical that's full of 80's music, so they pulled all sorts of 80's music. It's not a mistake to have songs show up in a year, in a completely made up timeline.
Revealing mistake: In the scene where "More Than Words/Heaven" is sung, there is a montage of shots of Drew playing guitar on stage and Sherrie singing outside. One of the shots of Drew has been horizontally flipped - in it he's now playing guitar left-handed and his "The Bourbon Room" T-shirt has the logo back-to-front.
Continuity mistake: Sherrie Christian's hair length changes by several inches from shot to shot throughout the movie showing the use of differing lengths of hair extensions used during the filming.
Continuity mistake: At the boy band gig at the Bourbon Club, Drew is wearing a red shirt and a coloured jacket. He runs off stage when he sees Sherree and they kiss. She tells him the jacket has to go and pushes it off his shoulders, Drew is now wearing a black vest top and the red shirt has disappeared.
Continuity mistake: When Catherine Zeta Jones is in the back of the car with her husband, she's holding a sheaf of papers held together with a bulldog clip. First the arms of the clip are up, then they're down, then they're up again.
Factual error: Tom Cruise throws the new Rolling Stone magazine at Paul Giamatti in the latter's office and tells him to look at page 68. Giamatti looks at and starts reading from the right hand page, but in magazines page 1 is the front page, and therefore subsequent pages on the right are odd numbers.
Factual error: In the Bourbon they use moving lights which were first used in 1980 actually the ones used were first produced in 1998.
Factual error: When Sherrie steps off the bus in L.A. you see the Hollywood sign, the Capitol Records building and the Roosevelt Hotel in the background. These landmarks are nowhere near each other.
Factual error: There's a poster on Drew's bedroom wall featuring the cover of Not Fakin' It by Michael Monroe, but the album wasn't released until 1989, and the movie is set in 1987.
Factual error: The Hollywood sign is shown as a tourist attraction with platforms, steps, and railings, but in real life none of these features exist and the area is gated and definitely off-limits to the public.
Revealing mistake: During the scenes where Tom Cruise and Julianne Hough are singing "Wanted Dead or Alive", several items in background have a mirrored image, including "The Bourbon Room" stage sign, an Exit sign and other signage. It does not appear to be an entire mirror image but rather just of a green screen.
Factual error: In the scene where Drew and his bands are seeing up on stage you get a clear sight of the drums. The drummer has die cast hoops on his drum set which did not come out till early 90's.