I asked David the same question regarding some of my boxing chip samples. (See my post below.) David's response was:

Regarding the notched chips with the Paulson reverse: "..a sample made for someone associated with whoever is featured on the chip."

Asked about the others that appear to be legit chips with notches: "notched by PaulSons machine which gives those identifiable 'scoops'. This would have been produced for the salesman, casino or gaming. Probably much scarcer than the other sample" [type].