60 - introduced in 1965
60-1 (1972) 3 in square butt limited production
60-2 (1987) DAO NYPD?
60-3 (1988) New yoke retention system
60-4 (1990) 3 in target sights full underlug barrel
60-5 (1990) DAO for NYPD with new yoke retention
60-6 (1989) Ladysmith version
60-7 (1990) front sight 1/8 inch wide, new heat treatment
60-8 (1990) same as 60-7 for NYPD
60-9 (1996) change to J magnum frame
60-10 (1996) Target variation on J magnum frame
60-11 (1996) New frame design for 38 Special version only
60-12 (1996) new frame nose cut
60-13 (1996) same as 60-12 but target version
60-14 (2001) Ladysmith with internal lock
60-15 (2001) internal lock on 357 mag target version
60-16 (2001) internal lock on 38 Special 2 in
60-17 (2001) internal lock on 38 Special 3 inch target
60-18 (2005) internal lock 357 Mag 5 inch target 2 pc barrel

Hope this helps.

Steve