In my area, assuming tight lock-up, timing checks out, and no evidence of erosion/flame-cutting around the forcing cone, with only minimal wear around the muzzle ... 350 would be -- in my opinion -- a very fair price for a nickeled finish 19-4. I've seen blued 4" 19-4s with moderate wear going for $450 - 475 around here.
I'd certainly buy the piece at that price; P&R 19s are my favorite revolvers and they seem to be getting more difficult to find (at least at reasonable prices) everywhere.