I didn't read the article, and believe it or not, I was pretty much oblivious to that series when it was on. I was living in a dorm room with no television set and pretty caught up in other things. So, I had never heard that it was "based on" two real cops. I kind of wonder to what degree it was "based on" anything since shows involving two cops on their beat seem as if they had already been with us a really long time--DRAGNET, ADAM-12 etc etc.
I presume Selby was a guest star on one of the shows and I would bet you dollars to doughnuts that whoever did that graphic is a DS fan...
G.