The C prefix was added to the Military & Police model in 1947 to designate the beginning of the 3 million to be manufactured. It became the model 10 in 1957. If I had to guess, based on dating of other weapons I have seen, I would guess yours was made in the late 1960's. However, if you call S&W they will be glad to tell you the exact year. Also, for a small fee they will send you the history on the weapon, which is exact day and shipping point. Enjoy your great weapon.