The basketball players at the gym practice are all members of the Los Angeles Lakers.
The Wagners' house is the same one used in Murder by the Book (1971), where it was the house of Ken Franklin. This particular house was used repeatedly in various "Universal" productions, including Quincy M.E. (1976) and several The Rockford Files (1974) episodes, among others.
The Los Angeles Coliseum stadium shots from the beginning of the show are from the 15 January 1967 AFL-NFL World Championship Game (renamed Super Bowl I after the term was coined in 1969). Kansas City Chiefs graphics painted on the end zone field and some of the Chiefs' cheerleaders can be seen.
At the basketball scrimmage, Lt. Colombo asks a man watching on the sidelines, "Where did you get those shoes?". He responds "Millers on Wilshire Boulevard." As of 2020, Miller's Clothing on Wilshire Boulevard is still in business.
When Lt. Columbo and Paul Hanlon are talking at the basketball court, appearances are made by Los Angeles Lakers players LeRoy Ellis, Pat Riley, Harold 'Happy' Hairston, Jim McMillan, and Keith Erickson. They are part of the scene, as Robert Culp's character Paul Hanlon explains to Lt. Columbo that they are some pro players who live nearby and like to get together and play for fun from time to time.