I think there would be a better chance of having an ivory set as a large percentage of ivory chips were carved in lower Manhattan. Weren't MOPs a European item?

I've found that many of the moguls of the 1920s and 1930s were members of the NYYC. I've also found that their twin burgee crest & seals were ordered through Abercrombie & Fitch. My theory is that A&F probably ran ads in the NYYC newletter for "top of the line, custom made sets of poker chips for club members". I would wager that the half dozen or so known burgee c&s made for NYYC members is only the tip of the ice berg. After all, what mogul wouldn't want a custom made set for their yacht, whether or not they even played poker.