Most certainly a Nitro Special if the bullseye pattern is on the left side of the top lever face. How do I know? Because your serial number is over 100,000 and I have one just exactly like it --- mine is a 20 ga. 28" bbls. chokes marked 2 (Rt.) and 4 (Left). Bought mine at a gun show a few years ago for $275 and thought I was getting riped off. Nowadays I see these Nitro Special 20's selling for $800 and up. So I guess I got a fair deal. Enjoy your old Nitro Special. Chopperlump