There is the exclusive proprietary distributor embossed rim mold designs, which are a safety feature, particularly in the old days to prevent counterfeit chips and ringed-in genric chips, from my web site:
http://www.antiquegamblingchips.com/molddesignindex_site.htm

You can look at these pages too:
http://www.antiquegamblingchips.com/steel_mold.htm
http://www.antiquegamblingchips.com/mfgchip.htm (the edge spots offered some protection)

Robert