Revealing mistake: In the scene where King Arthur expounds on the joy of his kingdom, he has a Band-Aid on the back of his neck. (00:21:00)
Other mistake: The copyright date is 1967. In the final title frame at the end of the movie, the copyright date in Roman numerals is incorrect. The V and the X are inverted. It reads MCMLVXII. The correct Roman numeral is MCMLXVII.
Revealing mistake: When they leave the studio to get into the taxi, there are multiple onlookers in the shot watching the scene from across the street. (00:06:00)
Revealing mistake: After Scott and Tom switch places, during the drive down to the hotel, in some close-ups there's black tape covering the motorcycle's chrome trim. (00:06:35 - 00:07:10)