Other mistake: Detectives Dundy and Polhaus visit Bogart at 3:40 in the middle of the night as we see the time on his alarm clock after they walk in. In the previous shot it's impossible to tell what time it is time because there are no hands on the clock. (00:11:10)
Other mistake: Sam Spade makes several telephone calls throughout the film using various dial telephones. On the first call, he dials a six-digit number, probably correct for the 1941 era, but on the following calls, he only dials two or three numbers and the calls apparently go through.
