These are the chips I got at a chip show 10 or so years ago. They are 39 mm size, plastic-molded-slug-core construction, but the core is not brass. It's some heavy white metal. The chips weigh about 16 grams... quite heavy compared to conventional casino chips.

I have some duplicates but would like to sell the set you see intact. Price for the chips is $2 each. Shipping is $3 for any number of chips. If you take the set shown, the price is $25 delivered in USA. Individual chips are $2 plus postage of $3 for any quantity.