The football footage is from the September 28, 1986, game between the Denver Broncos and New England Patriots which the Broncos won, 27-20.
First "Perry Mason" TV film to have been shot in Denver, Colorado. The last 3 were filmed in Canada; Respectively, "Perry Mason Returns" and "Case of the Shooting Star" were shot in Toronto, while "Case of the Notorious Nun" was shot in Vancouver.
Della says that Perry's relationship with Laura Robertson was 35 years ago. Perry says it was 30 years. With the events of this story set in 1987, that means that Perry was last involved with Laura Robertson shortly before the stories told in the "Perry Mason" TV series of 1957.
Raymond Burr walked with a cane in this program because of ongoing knee problems.
At one point, Della Street explains that she never got married, not even to Perry Mason. However, in the 1936 Perry Mason movie "The Case of the Velvet Claws (1936)" Perry and Della do in fact get married.