Mr Johnny they started stamping numbers of the model on the frame in 1957. Open the crane up and see what is stamped there. Like 10-1,10-2, or just a plain 10. Pricing varies around the country. Book says about $375 NIB, $275 EXC, $225 VG. I would say you could add $25 on to all these prices around here. Give me your serial number all but the last two numbers and I might be able to tell you more. Good luck. They were the original M&P.