I couldn't see any on inserts which I photographed.

I did read a couple of interesting posts on Pinside about the great dimple debate https://pinside.com/pinball/forum/topic/playfield-dimple-reality-check

It shows some photographs of Bally/Wms games with similar issues, albeit different photographs so hard to exactly compare.

I guess it is harder to notice on the older machines, due to use.  I guess for those of us who buy NIB and fold out nearly $10k are picky and closely inspecting every inch of the machine over and over.

I guess if you're concerned, buy a spare playfield, go the ceramic HRP treatment and be happy!