My P-01 is an '08 and I am using the factory (plastic) guide rod.
In your picture where you show the damage, it looks like the recoil spring guide rod only engages the cutout at the bottom of the frame - where it caused the damage. On my P-01, the frame is hollowed out on both the sides (as well as bottom) with stops/cutouts on each side. Therefore, my guide rod engages the frame at three points: the bottom like yours, the left side and the right side.
Maybe I'm not reading your photo correctly; or there has been a modification made since '06.
If I were to use a SS rod, I suspect that I possibly could have even worse damage than what you've experienced.
I'll try to learn how to upload a picture if necessary, but right now I don't know how to do that.