There was legal gaming in Mexico back in the 30s or 40s. A couple of different clubs chip show up from time to time on eBay.

There was a Foreign Club in Tijuana & Mexico City. This chip is from the Agua Calientie club in Tijuana. You can see others if you follow the link at the top of the index page to the chip guide and then go to the Crest & Seal chips - the non US chips are organized by country.