I just picked up a 91/30 from a buddy. It was made in 1940 by Izhevsk with a round receiver. It has stamps all over the stock. Some include numbers like 4,5, and a 6 in a box. Then there are letters like HH (not YY), P, D, U, A, and a C in a tombstone shape all in random places. Is there a meaning to these stamps? There is no scope mounting holes or a scope SN. The rifle SN is 56xx. I didnt know if there is a tracking page or anything. I would like to know more about the rifle. Anything would help.