Well, Frank, those are the same J frames I have for regular carry, although both of mine have CT laser grips. I started with the 442 but found that the way *I* carry it (IWB in a Kholster, outside a T-shirt but covered by a sweater in cooler weather, without a T-shirt but covered by a Hawaiian shirt when it's warm) I got rust on the inside surface of the yoke, where it mates against the frame, in a day or two if I didn't wipe the thing down every night with a silicone cloth. I know it doesn't sound like much to do, but I went to the 442 after years of carrying a Glock 26 the same way and never having a speck of rust anywhere with no regular maintenance.
I mostly carry the 638 now, largely because I just like the idea of being able to cock the hammer if I want to (and it's much easier to amaze the others at the shooting club with long range shots.) I have NO rust issues with it, despite no daily maintenance. I solved the hard-to-see-stainless-sights issue with black paint on the front sight and in the rear sight cutout and rear notch surfaces - flat black model paint applied with a toothpick.