Good catch. I was comparing it to my 1950 last night looking for differences, missed that. The roll mark, lack of tang d+t, d+t for scope, Pistol grip cap with white spacer and much thinner wood on the 1957 were different. Curious when they changed the hammer, is it possible it was around 57-58? I also saw where the R prefix could be 1958. Mine is in the 20k range R prefix. Whoever owned it was definitely was hard on the screws. And the crown indicates heavy firing. Curious how she’ll shoot.Great deal on your 39A!!
I'm not sure that the hammer wasn't changed out at some point in the past. I don't remember a 57 or 58 having the relief cut for the hammer spur.
Either way it's a great find.