I was never a fan of 'Magnum P.I.' but I've seen a few episodes over the years. And I ordered one disk from Netflix just to get a few screen captchas important for Toobworld.....
In "A.A.P.I.", Eugene Roche returned as old school private eye Luther Gillis when Thomas Magnum was to receive the award for Private Eye Of The Year (Hawaiian chapter).
Even though it was the local award, the convention attracted a few police detectives from the mainland, as well as the Surete detective who would be the keynote speaker.
He ended up dead, and even though that was the focus of the episode, I'd rather bring your attention to the three American cops who were in attendance: In case you couldn't tell (and I didn't get one of them at all), they are - from the left:
Lt. Mike Stone of San Francisco
Lt. Columbo of Los Angeles
Lt. Theo Kojak of New York City
Basically this is all you see of them in the episode. They had no lines and no reference was made to their presence in the crowd. So I'm willing to accept that they are the real characters.
And I'm not the only one. The Wold Newton Universe has accepted them into its company as well.
Being played by other actors, there were of course some differences in how they look. (Mike Stone was the one who didn't really work for me. But that may have been because of his drastic change in wardrobe.) In general, I'm going to attribute any physical discrepancies to the rigors of long distance travel. Because of scheduling, they had to go to the convention straight from the airport.
Kojak and Columbo became nationally known figures, so they could trade on their well-known visages. As for Mike Stone, it wouldn't matter if people didn't recognize him - he was probably carrying his American Express card.
I'll bet he never left home without it......