This is the only time in the series the character Banacek appears before the opening credits.
At the abandoned Army base, the kidnappers are located in an old barracks where a number of pinups are on the walls. Behind Al Bates in plain view is the centerfold of Carol O'Neal, the Playboy Playmate for July 1972, making her the first nude woman to be shown on network TV.
Banacek's chauffeur offers a solution for the missing player by saying they cut a slit in the turf where they hid the player. While it was meant to be a joke here, that idea was the basis of a solution for another case Banacek would solve later in the season.
The chess match they mention is the Boris Spassky - Bobbby Fischer World Champoionship in the summer of 1972. Because of the Cold War tensions at the time, the matches were televised on TV, an unheard thing to do at the time for a chess match.
At 42:14 there's an establishing shot of now demolished Schaefer Stadium in Foxboro, MA, at that time the brand new home of the New England Patriots.