When Hitch is being shaved, his assistant Peggy (Toni Colette) comments that 20th Century Fox is offering him to direct The Diary of Anne Frank (1959). The scene happens after the Chicago premiere of North by Northwest (1959) on July 8, 1959. To that date, the film version of The Diary of Anne Frank was already finished and its first public show had happened on March, 1959, at least four months before the Chicago premiere of North by Northwest.
Dean Martin's recording of "Ain't that a Kick in the Head" plays when Janet Leigh meets the Hitchcocks prior to the start of filming. Filming on Psycho ended on February 1, 1960. The song wasn't recorded until May 10, 1960.
When Hitch is finished being shaved in the barber's chair we see shaving cream residue on his cheeks. When he looks at his reflection in the hand mirror, the residue is gone, but when we see him from the front again, the residue is back.
At two occasions we see the famous Bates Mansion in the background, facing the right side of the house, opposite of how it appears in 'Psycho'. Originally the house was constructed with only 2 walls - the left and front facade.
In the on-set scene in which Arbogast (Martin Balsam) is about to be stabbed, Anthony Perkins' character is seen sitting nearby in drag as Norman-as-Mrs.-Bates. In reality, Perkins was not even on set this day (Hitchcock used a female "little person" as a double so audience wouldn't be tipped off to the murderer's true identity by Perkins' height.) In fact, the only time Perkins actually appeared onscreen as Mrs. Bates was during the fruit-cellar climax. Doubles and stand-ins were also used during the shower murder for reasons of convenience and deception.
Portrays principal photograph and Hitchcock's office as being on Paramount Studios' backlot. In reality, as "Psycho" was the last picture the director would make under his contract with Paramount, by the time filming began his office as well as the sets had moved to his new studio: Universal.
In the scene where Hitch is seated in front of his TV set watching a cartoon while listening to a classical record album, the piece that is heard, which is correctly credited, is the scherzo movement from Beethoven's 3rd Symphony (Eroica). However the record album cover that is on top of the TV-stereo console is entitled "Beethoven Overtures."
The goof item below may give away important plot points.
Hitchcock's (Anthony Hopkins) final words in the film are to the movie audience (us): "Good evening", as if closing an episode of his television show. "Good evening" was what the real Hitchcock opened his shows with. He always closed with "Good night."