When making change, the waitress at the diner in Sentinal Mesa hands over real one-dollar bills. Usually, prop money based on defunct Mexican paper currency is used.
The vent windows, front door frames, overhead rear view mirror, windshield wipers and, in some scenes, the front windshield panes have been removed from the professor's VW Bus, perhaps to get a better view of the actors. The VW logo was also missing, perhaps to avoid giving VW free advertising.
Macdonald Carey and Edgar Buchanan had been castmates in two films earlier in the decade, The Great Missouri Raid (1951) in which Carey played Jesse James and Cave of Outlaws (1951) which had a story bearing a resemblance to the similar "Hitchcock" episode Enough Rope for Two (1957).