I would think S&W would put it in the M&P line first to try and cut into G20 sales. And considering they probably sell more M&P's than any N-frame revolver.
Actually I'd rather they do that.
I have one. A 64-5. Even though I generally dislike fixed sight revolvers, I bought it for a steal and originally intended for it to be a project. It just sits in the safe taking up room.
I'd have no qualms with getting another PD trade in, assuming I got to go over it before hand.
That is a round butt frame.
Looks like it's been shot quite a bit, with hot 125gr rounds, by looking at the forcing cone and the flame cutting. The forcing cone is a fairly straightforward fix by a competant gunsmith.
Usually flame cutting is self limiting. Meaning, it'll only go so far, and...