Because of the fire and loss of serial number records, we can't really know for sure. @nit wit is probably close for the first serial number. The second serial number is probably later in the 1970's say '74 to '78. The third number is most likely from the mid to late 1980's. The actual date of manufacture really makes little difference in performance, reliability or financial value. What matters is the condition. So continue to take good care of your rifles.