I have had several sets of casino ivories in my possession; none had the "50" chip. However, I do know that on the river boats gamblers had special ivory chips in amounts from $25 to $100 (perhaps more) with their initials or names and the city of origin (New Orleans) which chips represented IOU's. The holder would get that amount of cash when he presented the chip to the debtor (gambler) in New Orleans. The last time I had a chance to buy such a chip (for $25) I had spent all my money and the non-local dealer wouldn't take my check. He promised to wait while I drove into a nearby town to an ATM. When I got back it was raining and he had packed and gone.

As you can see, it doesn't take much to tell a story. <g>