Welcome to this forum! The "R" with a number in a circle on the barrel and receiver is a 1964 manufacturing date. The meaning of the numbers themselves inside the circles are unknown at this time. The 1964 date is correct for the Westfield, Mass. factory. The numbers under the barrel in front of the lug and on the top inside rail are "assembly" numbers. If matching assembly numbers are found at those two locations, plus stamped in the stock, under the butt plate, and sometimes stamped in the wood inside the forearm, this is a good indication that the gun is unaltered since leaving the factory. If you have time, please check under the butt plate to see what may be stamped there. The barrel appears to be "C" over "JH" over "21". The rail appears to be "21" and "IX" (not 1X). I think if you find any combination of these under the butt plate, it will verify a matching gun. Thanks for sharing with us! Best wishes!