Not really a counterfeit; made after the casino closed as a collector item. Lots of people collect such commemorative items (including a certain GeneT ). TCR has it worth $25 retail. You should disclose its history if you sell it.

I bought a set of high denomination items from Mr Osborne on the floor of the Convention nearly 20 years ago. I didn't find out for a year or so the full story.

Picture from the Club web site on Fakes, Counterfeits, and Fantasies: