The copy of Playboy that Jerry is caught reading is the June 1976 issue featuring Playmate of the Year Lillian Muller on the cover.
The postman mentions that film with Rod Steiger, which of course is No Way to Treat a Lady (1968), but asks Barbara whether or not it was made by MGM. This film, which also starred Lee Remick, Eileen Heckart, David Doyle, Val Bisoglio and George Segal, was in fact produced by Sol C. Siegel Productions, and distributed by Paramount.