I also find the absence of the R-N puzzling. That is why I tend to think the gun was originally nickel and had a blued cylinder installed. Maybe that is why there is a star on the yoke, as well as the frame. But that is a guess on my part. I also don't know why the frame star is on the side of the grip frame, instead of its normal location on the butt.What I do find odd is there is no refinish mark on the frame which would have been R-N, or the same letters contained in a cartouche or rectangle. There is also no "N" on the frame to indicate it was originally Nickel. Maybe Jack could shed some light on when that marking began on new guns, this could be before that date???