I'm convinced I have a variation on the old Bud Jones house mold chips at the Eldorado. I found some where the edge is more "bowed" than others, and the white plastic is much less reactive under the blacklight (same distinction consistently together). There's nothing I could show you in a scan that would show you the difference. Only a real variation freak would even believe they were different. In a rack of 100, there were less than 20 of these, that I believe to be older. I have some of each if anyone is interested.