Looks like the leftovers were sold in a downtown giftshop in the 1960's.

This description was from when the seller was selling these on Ebay in 2009. I remember he had at least 10 of them for sale..maybe many more. I bought 5 of them at the "buy it now" price of $10 each:

This auction is for one Sans Souci card room 12 1/2 cent casino chip. This chip is new and has never been played with. I purchased them in Las Vegas in 1962 or 1963 at a gift shop in downtown Las Vegas after the casino closed. They were brand new still in the factory sealed package. They have sat in one stack in a chip holder in my basement for the last 45 years. This chip books for $100.00.