Anachronisms: The cameras in the Comedy Cavalcade studio are RCA TK-14s, which were not introduced until the late 1950s. (NBC would have used RCA TK-30, TK-10 or TK-11 cameras for black-and-white shows at this time.) In another scene a Marconi Mark IV camera is being pushed through a hallway; this camera also was not available until the late 1950s.
Anachronisms: When Benji follows Alan Swan to his limo in front of Rockerfeller Center just before the big climax, U.S. state flags flying in the background include Georgia's state seal/Confederate battle flag design, which wasn't adopted until 1956.
Anachronisms: In the street scene following the "hot dog" shot, the block Benjy and Swann are walking in is a real NY street dressed for 1954. The next block behind them and the skyline including the long-gone Astor Hotel is a matte shot. Watch under the marque over the left sidewalk and see several modern buses and an RV go by.
Anachronisms: When Swann is dangling off the side of K.C.'s parents' building, all the cars seen on the street below are plainly 1970s and 80s automobiles, though the film is set in 1954.
Anachronisms: In the family dinner scene, Belle calls Alan Swann "Al," to which Benjy responds, "Ma, it's not Al. If I invite Capone or Jolson, then it's Al." At that point, Uncle Morty says, "Jolson's coming?" The movie takes place in 1954. Al Jolson died in 1950, and Capone died in 1947. Of course, Benjy could have been making a facetious remark, but Uncle Morty acts as if he thinks Jolson is still alive.