These were made from 1983 to 1991. Didn't sell too well. S&W was late to the game as far as silhouette shooters were concerned.
They all had 10 5/8" barrels. That adjustable front sight could also be ordered on other Model 29's. I've handled a couple of 29's with 6"
barrels that had them, but that's been several years back.
The one I have left the factory in March of 1989. If you do a search, on this site, there are instructions on how to adjust that front sight.