observation, but... Is it possible that they are high-density cardboard and not plastic? I ask because I have some of those, both as individual discs and as die-cut sheets. The die-cut sheets have 6 or 8 (going from memory here) discs and each one reflects a different casino name.

The same foil printing is used, i.e., hot-stamping, but mine are definately cardboard, as I doubt the manufacturing process would be die-cut plastic.

Jim