The 629-2 Mountain Revolver is a neat variation, it's the grandaddy of all Mountain Guns because it came first although by " first" it's not that it premiered something new as much as it paired a bunch of existing features into a package not offered prior.
Only weakness is that the 629-2 is pre endurance package.
The 629-2 MR version is a bead blasted type finish which is pretty but the downside isthat u can't remedy scratches in the finish with scotchbrite like u can with later matte finish guns, it also shows holster wear more.
The bead blast finish also makes the turn line jump out more so if u don't like turn lines be warned.
The barrel contours are generally the same as later versions although u do get actual rollstamps instead of the thin laser etching stuff found on later guns, you also get the old grooved tangs if that excites you ,
Lastly the dash 2 has the "Notched" frame at the front like the older narrow rib guns such as the older Model 15 and 67, down side is forget ever swapping a different barrel as standard 44 Magnum barrels have a wide rib.
In a pinch u could use a 44 special barrel from a 624 by shortening the forcing cone but those say .44 Special.
An interesting variation exists that have the old Magna porting with one long thin slot on each side of the front site, rumour is that SW sent some new guns to Magnaport who modified them , not sure if thats true or not.
Lastly the 629-2 Mountain Revolver is unique in that it's the only Mountain gun variant to have come with those Pachmayer grippers from the factory.