I found a few of these in a dealer's junk box. It's gray in color. The center has been cancelled by drilling the center down enough to remove the hotstamp on both sides. I suspect they may have been the $1 chip N5024 before cancellation. All have the same little hint of hotstamp in the 9 o'clock position where the center of the circle is left undrilled.

All that I found did not appear to have been used in play before or after cancellation.