I have an old Silver Age Rye ad chip. I notice in Dale Seymour's book the reverse of the chip has a 50 denomination on it. Mine has the same thing on both sides. i wonder if different colors of the chip had different backs? Or is this just a variation of the chip? It says it's stamped paper but, it seems more like a fiber chip. It has a nice ring when it hits the table. Anyone know about these chips?