The Silver Slipper chip has a somewhat uncertain history. It is listed in both TCR10 and The Official U.S. Casino Chip Price Guide. It is possible that it was at one time used in Las Vegas, but it is not confirmed. My understanding is that it will be delisted in TCR11 and will probably stay in the next issue of The Official Guide. I do know that it is currently in use during the Klondike Days celebration in Edmonton, Alberta, Canada for 10 days a year. It is quite possible that it was previously used in Las Vegas, but are looking for confirmation. I purposely listed it here looking for more information. Thanks.