I have a series 70 GC NM. In looking up the serial number all in this vintage seem to have NM in the number at the beginning. Mine is 13XX2N70. The slide says Gold Cup and the trigger and rear site match what should be about a 70's vintage run. Is my research flawed regarding the number or is this thing a parts gun??? Thanks in advance for the help!!!! Wanna kill these ads? We can help!