To throw a fly in the ointment:
(a) many chips don't have edge spots, so the curved (concave) edge spot rule won't help with those chips; and
(b) as Jim e-mailed me and as I have seen on many chips, it is hard to tell if the edge spots are curved or straight on edge spots 1/4" or less. In fact, I get the feeling that many of the edge spots on Burt Co.-made chips ended up having straight bottoms to their edge spots. [Burt, I take it, made all the H C Edward chips. The chip at the top of the picture below has a classic Burt EDGE SPOT -- the bottom (inside end) of it is curved -- that is, parallel to the curved rim/edge -- that is, concave. Jim has told us that all of the Christy and Jones chips were made by Burt, and Burt always made/punched concave edge spots; therefore, hat and cane chips with concave edges spots are Christy and Jones chips (or at least, if it is a hat and cane chip AND the edge spot is NOT concave, it CAN NOT be a C&J chip), if I got all this correct. But the problem is that the eight chips on the bottom of the picture below are made by Burt but sure do not look like they have curved/concave edge spots.] {Incidentally, I'd trade these for other distributor advertising chips.}

Robert