No gunsmith recommendations but when I was trying to figure out which 629 I wanted to buy, the 629-3 kept popping up as the lowest number I would really want and the 629-5 as the highest. I pulled this off another forum:
Mod 629: introduced in 1979.
Mod 629-1: Eliminated the recessed cylinder and the pinned barrel (1982).
Mod 629-2: Changed the yoke retention, made internal changes to the action, including a floating hand, and added integral scope mounts on the 8 3/8 inch barrel (1988).
Mod 629-3: Internal changes - fixed hand, longer stop notch and added bolt block (1989).
Mod 629-4: Extractor changes, different sight leaf; frame drilled and tapped for scope mounting (1993).
Mod 629-5: Internal changes to the lockwork, new trigger and hammer systems, eliminate cylinder stop stud, smooth tangs replaced serrated tangs (1997).
Mod 629-6: Internal key lock system (2001).
Mod 629-7: 2-piece barrel (2005).
Mod 629-8: Introduced flat sided barrel (2006).
The Model 629 Classic Stainless with the full under-lug barrel followed these same design changes, but wasn't introduced until 1990 with the dash 3 changes already in place.