Good explanation guys. The dash number, as explained, is unique to an individual model. Doesn't cross over to another model as a way to determine vintage, even with models that differ in only blued versus stainless. For instance, on the Smith 44 mags, the endurance package was added to the stainless 629s with the dash 2E or 3, but since the blued 29 predated it, the 29 got the entrance package at dash 5.
In general, the pre-early 80s Smiths with the pinned barrels and/or lack of a lock (some models like the 686, 629 came after pinned barrels) are the best way to spot a potentially collectible Smith. The pinned barrel was an added measure to secure the barrel to the frame, but wasn't really needed. It's not an obvious big pin, but if you know where to look, you'll see it. It's a tiny pin above the the spot where the barrel is installed in the frame, as with this early 70s vintage 28-2. If you look at the pic of Dave's 19, you can also see it.
