There is no advantage. It is just an easy way to tell a pre-1982 M29 from a newer one.

As far as the older ones being made better that is absolutely false. Smith and Wesson developed the "Endurance Package" and all 1988 and later models have it. It includes better heat treatment of the yoke to make it stronger. The cylinder locking notches and the cylinder bolt are longer and deeper on endurance package and post package N frames. The trigger and hammer pivot pins were improved to prevent shearing off like the older models started doing after many many full house loads. Also the cylinder notches were cut deeper and a stronger cylinder bolt lock was used to prevent backspin to another chamber as some started doing after hard rounds. Also due to modern machining the fitment and cylinder lock up is a lot tighter than the older ones ever were. These are just straight facts and anyone saying otherwise is just being biased toward their favorite older model. Yes they were nicely blued but I would put a newer M29 up against an older one anyday and a novice would pick the newer one every time. They are doing a lot better than they were at one time. The finishing is very very high quality and shines like a mirror. There is simply no way it could possibly look better.

The newer ones are made stronger but still look nearly identical.to the older ones