Jim, yes, forgot about those. I have the same 5, from John Berg (RIP) in 1994. Those, of course, are not old enough to be rated "antique" gambling chips I suppose. Not in the book in the non-overlay condition, if they even exist non-overlay. They could be all-plastic; I have not taken them apart.

I also see that I have these too. They are made encased in interlocking "airtites." Have a flat surface. But inside they look like metal-clad embossed chips. These are likely all-plastic. No dupes.
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Robert