Hello. As the company did once in the recent past with a batch of lockless Model 37 revolvers, S&W has made a run of 642's not having the much-debated lock on the side along with another batch of Model 37's. I've heard that both of these aluminum-framed Airweight members have the "-1" designation though some advise that the M37 has a "-2". I have not seen one of the new-run Model 37's so I cannot say based on personal observation. Both come with the same style rubber grips seen on these snubs. A friend of mine bought two of these and we shot them yesterday.
Fit, finish, smoothness and trigger-pull felt about like others of this tribe, ie: no surprises.
POA matched POI out to about 10 yards (we didn't shoot too terribly long due to the heat) though various steel plates were smacked almost every shot at 15 yards. Perhaps 100 to 150 rounds per gun were fired with exactly zero problems.
I have seen conflicting numbers on how many of these S&W is making. What I've seen says from about 1000 to about 4000. I am not in the market and have not checked further. If you are, you might (quickly) check with your dealer if preferring a snub w/o the storage lock. I think that they will sell quickly if they've not already all been sold, being the exceptions rather than the norm in these days.
Admittedly, two is not "statistically valid" but both worked just fine.