Extractor ratchet teeth are different. Extractor stem is hexagonal, not square. Extractor stud is eliminated. Frame is altered for hammer block safety. Front sight is colored brass in place of steel.
Front sight is pinned in place in lieu of being a one-piece forging.
Hammer block safety is added. Hammer is altered for hammer block safety. Hammer stud is polished flush with frame. Hammer stud has no spanner wrench cuts. Joint pivot diameter has been increased.