I'm not sure here I've had my kimber sitting in the gun cabinet since sept 11 2001 , that was the last time i had any gunsmithing done to it. BUT I have a Stainless Fullsize serial number K028xxx. I am assuming that it is a series one since it doesn't have a 2 anywhere on it except the serial number. I will post pics of her soon , it took me a while but i changed out all MIM parts on it. Only thing left on it original is the slide , barrell, and the frame, everything else is Ed Brown or Les Baer , oh and the Novak Trijicon bar dot site set up. nicely trimmed out with electric blue Kim Aherns wood grips.