Paul,

They are probably "Fantasy" chips that were made and sold after the casinos closed. One way to tell is that the fantasy chips have the opening and closing dates on them. They also have a "mold" (indented lettering in the clay rim) the has "NEVADA" and cards and dice.

These chips sell for around $1 apiece at the Gamblers General Store in Las Vegas.

You can check out more "fantasy" chips at the following website:

http://www.ccgtcc.com/fantasy.htm

This is a page on the Casino Chips and Gaming Tokens Collectors Club (CC&GTCC) website.

I hope this helps answer your questions.

Scott