Most I have seen are historocal reproductions.

Archived here are my posts showing many of the originals; mostly rectangular and square... of which were made in the same exact manner as ivory gambling plaques from India.

Some of these reproduction rounds have been mounted and sold as bracelets as the American repro types of riverboats, Guineas, Hanover St, and such... Several of us saw the actual bracelet at the 1998 Biloxi show. That same piece has been offered here as well.

They do command rather lofty prices... especially when purchased as gifts.