Character mistake: When Andy and Barney are looking through the yearbook, Barny's middle name is Milton. But Barney says many times throughout the series that his name is Bernard P. Fife.
Character mistake: In "Movie Maniacs," the Three Stooges arrive in Hollywood via train, sneak into a movie studio and walk onto the set of a movie being filmed. A starlet looks at Curly and says, "Oh, Mr. Howard." There is no way she could have known his name.