As I said earlier My Tron & TWD & ACDC had very minimal dimples but ST had a few that's maybe due to color tones that showed them up easier,  to be honest it never really worried me I mean that ball is hard and it'll do damage its pinball :) some even put plastic protectors on to save damage. If Stern spent more money putting 10 layers of clear on then we'd all be complaining about price increases lol remember it's made for operators to put on site and make money :) op's probably don't care less as long as coins keep coming in.
I know other guys with NEW games and I've never heard them complain.