The original was actually the 629-2 Mountain Revolver and most of these came in a matte stainless finish and were made in 1989. The Mountain Gun was made starting in 1994 on the 629-3. the - revisions follow the rest of the 629 line. The -3 revision included the endurance package. The -4 changed the rear sight and added a drilled and tapped frame. The -5 changed the frame to eliminate the cylinder stop and intoduced MIM lockwork. The -6 brought the Hillary Hole.