"I wouldn't be surprised to learn that some of David's repaired chips have since been sold by his customers without disclosure of the repairs."

Surely you jest. Just because some of our chip dealers are having 6 & 8 of the same clay chip fixed does not mean they are re-selling them!

"are these repairs only on flat clay areas or are holes in the actual mold itself being repaired also?"

The only one I actually saw had been drilled through the inlay. I have to draw on memory which is real bad but I think it was a Cal Neva $100.
I had a conversation with Dave about fixing holes not in the inlay, I am pretty sure he said he can do it in some cases.

He is also fixing damaged inlays like ones glued to displays. One dealer brought him a quanity of the same chips with a ruined inlay on one side. He removed and replaced the bad inlays and made 1/2 of the chips good. This was per Dave.

I also saw a counterfeit 50¢ chip. Made totally from scratch. Blank NV mold, home made inlay. It was perfect.