Found this set of "A. Girpo Ltd." celluloid advertising chips at Dale's table at the convention. They are catalog PY-EW in his reference. Colors are Red, Dark Purple, Green, and Yellow. The material in all is translucent, but the purple just barely so. The images appear to me to be hot-stamps, although Dale calls them engraved. The design fill is in gold.

I have an extra of the dark-purple chip for $12 delivered.

If anyone has other colors, I'd be interested.