I just acquired a like new 36 RB with a 3" barrel and large SQ grips. The revolver is like new ser. no. J203xxx so think it is from 73-74 era. Previous owner was a city officer that basically worked with grade school children in a large city years back. Large for Wisconsin anyway. I had one years ago but foolishly let it ago, so was glad to get this one Almost a shame to shoot it, but then again it's the reason I got it. Am going to get a set of UMs rubber grips for it like I have on a 2" 36. Is it possible that the larger SQ butt grips may have came on the 3"er?