Although I can't tell you the exact date of manufacture of this gun, all Nitro Specials, were (as the name implies) modern guns designed for modern ammunition. While shooting 1 1/4oz 16 gauge loads is possible, if unpleasant, most defer to a guns age, and use slightly lighter loads in their old nitros.
Nitros may be the ultimate good deal using gun in todays market.
Best,
Ted