I have a finger grooved stock which appears to have had the second stock bolt installed duing the over haul process. Aside from the proof mark, the only discernable mark is a boxed "PODM" on the left side forward of the wrist of the stock. The "M" is serified, the other letters are not. The "D" is only partialy visable, and it could possilbly be a different letter. Any ideas? Thanks in advance!