I won't use 'em. Not because they hurt the finish, but because they aren't very good at retention and they don't wear well. Most of us that have been carrying for awhile have spent enough on holsters trying to find the right one that we could have gotten a new pistol. Or two or three.
I suppose if it is a holdover, that is okay.
But some advice would be to immediately order a good leather one (Milt Sparks VM2 is my favorite, I have three) and a good leather gun belt. Those two things are at least as important as your pistol is for carry.
Milt Sparks will also take a few months to get it done, so you need the CC number now, but they won't charge it until later --just make sure you have money on the card in a month or so just to be safe, if they try and charge it and it comes back empty they won't call or anything. Too busy, they don't NEED your business (as much as I need theirs!).
Good luck. And forget about the finish on a carry piece. It will wear no matter what. Blued finishes and whatever Beretta uses wear pretty easy, but they won't rust (Beretta anyway). Glocks just take it with a grin, that is what I carry.
I have one from the '80's that was used as a police pistol for a decade, then I got it, shot the snot out of it, I've carried it, my wife has, on and on. The finish looks about the same as the G21 I got fifteen years ago but seldom use. Not now though, it was a test mule for Duracoat so now it looks like a new one.
Finally, cheap holsters will cost you more than a good one in the long run. Trust me here.