I always thought they were something else - look at the pic. I thought they were chips sold in the gift shops in the mid 80's. Just came across this the other day.
http://www.ebay.com/itm/Vintage-HARRAHS-Casino-Chips-Clay-Based-in-original-box-120-Casino-Chips-/251309004468?pt=LH_DefaultDomain_0&hash=item3a832f16b4