I bought my 642 ~3yr ago online, and WITHOUT an internal lock. That model is STILL available without the internal lock. A valid option for those concerned.

The 642 without the lock is a good/great SD carry, IMO. I've carried it for 3yr but recently shifted to a SS framed K6S, capable of .357 rounds. I am seriously thinking of keeping/using the K6S with only 38Spec+P for carry. Much more controllable rounds IMO, particularly, in a lightweight (23oz).

I have both a 686 and 627 for the big rounds and will keep them as "Range Revolvers", as least for now.