At least with wheel guns, and now non-plastic 9mms(Berettas, 3rd gen S&Ws, etc) a lot of "police guns" out there these days tend to be corrections or private security guns.
I've found that these often look like [censored] on the outside, but have been meticulously maintained by an armorer and have been shot very little.
My last "police" gun was an S&W model 64. This is the stainless steel model 10 equivalent. Mine has a 4" heavy barrel. It is factory double action only, with no single action seer and a bobbed hammer(made that way-not a dremel job). It is a pre-MIM gun-I'd guess late '80s.
The sideplate is badly dimpled and scratched-it looks like a set of keys banged against it for years(making me think it was a corrections gun). The grips got switched to a nice but not perfect set of Goncalvo Alves Magna grips as soon as I got it home from my FFL. I have the "originals" as a conversation piece-the originals have the left side checkering gone completely and the left grip has about 1/2" of missing wood on the bottom from nothing but wear. In other words, it was carried a lot-probably in a hip holster on the waist of someone a bit on the "rotund" side.
Even so, the bore was spotless and I doubt there had been 200 rounds down the pipe. It's my preferred nightstand gun, and I've been known to open carry it(although I now usually use my 19 for that). If you read Massad Ayoob, the fact that it's double action only makes it almost an ideal gun for self defense.