In answer to the OP's question about old versus new Smith Airweight revolvers here is my experience with a couple of them. The "old" S&W Centennial is a Model 642 no dash I purchased new in 1991. It has maybe 500 rounds or so through it and now has what what I consider a smooth trigger and has held up great showing very little wear from being carried a lot. It weighs exactly 15 ounces. Just to have a spare I bought a new one in 2022, a Model 642-1, again in 38 Special WITHOUT the lock. I haven't shot it a bunch but it had a very good trigger right out of the box. It weighs 14.5 ounces so a tad lighter than the early one. This 642-1 is on the Magnum J-frame which is about an eighth of an inch longer and also has the longer .357 Mag cylinder even though still only chambered for 38 Special. It does have the MIM internals instead of the forged internals which are possible lighter? It also has the original type one piece barrel but also has an overall coating of some type on it that seems rather easily marred and will wear quickly. It's just me but I much prefer the older one. Either way I believe that they are great. And FWIW they are now loaded with Mackay Sagebrush's standard pressure wadcutters.
