Some years ago I found a 50 cent chip from Ocean's Eleven Casino in silver hot-stamp. I was told by other collectors that many (if not all) gold hot-stamped chips are made of gold applied over a silver undercoating making the gold look more sparkly. (Logical way of doing it, the material used in hot stamping is a double-colored sheet consisting of a silver layer and a gold layer.) I don't know if that's true. Anyone knowledgeable about how chips are hot-stamped?

It is possible that in your case, both gold and silver hot-stamped chips were made (some casinos seem to like tables full of gold AND silver sparkly chips) but I would think someone would have reported the two colors long before now.