I think there are about two people on this entire forum that have pronounced peening. I've got 4 PPS (3 original, 1 M2). All have been fired and came to me used, and I've fired at least a couple of them. Two have zero peening evidence. Two might have the slightest possible hint under a magnifying glass of the peening. I'm going to monitor but I am not at all concerned.
The PPS has now gone down to sub $300 used in my area, nearly disposable gun pricing. I wouldn't lose a lot of sleep over a perceived "peening" problem. Which Walther doesn't recognize as a problem anyway. I've not heard any reports of any problems caused by it either.
If you're still really unsure on the PPS, go with the classic. It's a better gun IMO and the ergos are more akin to the P99 anyway.