Isn’t Celcon also a type of POM. The way it was explained to me in the past is that Celcon is poured into a mold while Delrin is machined like aluminum.
Is the Regen molded or machined? Either is fine, I am just curious.
As for the gouging issue, yeah that is normal. I used an old Lyn Fury when I first started learning 5A and I marked the heck out of that thing. Mostly from hits to my wedding ring and the counterweight which was a 20 sided die I turned into a counterweight. The way I looked at it, I was swinging another piece of plastic at my yo-yo that was not attached to my finger, marks are going to happen.