Kydex doesn't scratch guns, it's the crap that gets in them that causes the scratch. Leather has more give & the grit tends to be pushed into the leather. Get enough junk in a leather holster & it'll scratch up a gun too.Henny
I think those scratch marks are probably from Kydex. My 31 has been carried exclusively in leather and doesn't show any slide wear. The paint is completely gone from my slide stop.