Personally, as soon as I saw the FNR stamped markings I thought that they were too recent. If you see stamp markings on rifle woodwork, after a year or so, the wood seems to close down on the marks as though it is sort or repairing itself if you like. You can always see them but they just don't look fresh. Full of oil and grease and grit. We used to see lots of BW and FWA or FWM and SO that came through and you could just tell that they were much older marks wqithout even looking at the date codes. Just my opinion for what it's worth