I inherited this Model 15 from my father when he passed. As I recall, he received the gun from his brother (also now deceased) but from there I have no idea how the gun was acquired. I decided a few years ago to have the gun lettered and according to S&W, it was shipped in 1973 to the Navajo Nation in Arizona for what I assume to have been the reservation police. No markings but some honest wear on the bluing.
The stocks are some PC magnas I added as I was carrying at the time. It now wears the numbered magnas it shipped with.