Continuity mistake: In the scene in the Beatles hotel room where Nancy Allen comes out from under the cart with the cokes on it, when she first sees the Beatles' guitars, notice that in the very first scene, the Hofner bass is left handed (the pick guard is on the left as you're looking at it), then it cuts to her, then when it cuts back to her rolling on the floor with the bass, it's suddenly right handed, then when in the last scene with her handling it, it's left handed again.
Factual error: The movie is set in New York. When Tony Smerko goes up on the roof of the studio to chop down the antenna, there's a green Art Deco building with a clock tower in the background - the Eastern Building, a downtown Los Angeles landmark since the 1930s.
Factual error: The hotel room would not have been empty when the girl sneaked in, because George did not attend the Sullivan rehearsals. He stayed behind (presumably with an attendant) because he had a cold that week and was trying to recover before the actual show on Sunday night.