Paw-in-law has gotten ahold of an old Mossberg .22 rifle and wants to know how old it might be. I've been googlin and saw it was forsale in a 1938 catalog but don't know how long this rifle was produced. Barrel is stamped : O.F. MOSSBERG & SONS INC. NEW HAVEN, CONN. U.S.A NO. 46B 22 S-L-LR PATS. PDG It also has a scope MOSSBERG-NO. M4(b) 4 POWER-PAT. PEND. Any idea how to find out how old this thing is ?