~~~ on the pieces and curious about the pieces with the crude, hand-engraved serial numbers.

Last night I found additional notes that they may have been for either a private club or personal use, but I seriously doubt there are 'thousands' of them.

I remember first seeing them introduced to our hobby in the early-1990s and pics of them in Michael Knapp's club magazine column "THE INFORMATION BOOTH" and that's when I started searching for an attribution by askng friends in Europe who were collecting for 30-years prior at the time and they had no information at all [I have additional notes in storage]. Then, some coin dealers in California suggested the "CEP" meant CASINO ELYSEE PALACE -- but there is nothing showing this.