I guess we all have a theory. Mine is that the double holed chips came out of salesmen's sample books. The USPC records are salemsn's sample pages. The single holed chips (location is usually 12:00 or 6:00 o'clock) were attached to the front of a box of chips. I have seen a picture of a box of USPC chips with a chip attached to the front through a sungle hole. If there was a 20 box order, a chip would probably be attached to only one of the boxes. I guess the single holed chips are rare!! BTW, very rarely is there any wear and tear on the holed chips. If I find a chip without holes, the holed one goes!

BTW, I am referring to the pin holed chips. The chips with the large holes (Nevada c&s, Cuban GL, El San Juans, etc were down by the owner of the chips not USPC.