This appears to be an overstrike. I have a number of them. Most of mine came in a box with chips that were destributed by a Frank Walters [several had his initials on them] and I assume they were salesmen sample chips. What I don't know is whether overstruck chips were once in play and were overstruck in order to void them--but that would seem to be an unnecessary expensive way to slay them. Gene can probably shed some light on them.