Martin Landau and guest star John van Dreelen previously worked together in the classic The Twilight Zone (1959) series episode, The Jeopardy Room (1964).
The car Willy and Barney are driving when they "steal" Cinnamon's diamonds is a Morris Minor 1000 Tourer Convertible.
Hand written autographs have real value for traders who make a living by selling them. Nonetheless, some personalities have used a rubber or steel hand-stamp to "sign" their documents, such was the case of President Franklin Delano Roosevelt (FDR). That's why Briggs asks for the rare initials in his own hand.
All the agents use there real names instead of fake ones during this caper.