You should get Janice O'Neal's list of Nevada tokens, Jim. She lists the mint for each token and there is a list of all mints that have produced tokens at the front. I believe there are only 3-4 companies currently making tokens for the Nevada casinos but didn't check the list. I know there are many tokens without a mint mark, but Janice has provided the mint info in her list in almost every case. You also get a catalog number (O'Neal #) for each Nevada token to help you in organizing your collection and talking to other collectors about specific tokens.

Maybe Janice will also see this post and give the info on how to order the current list. There is a charge, but it is very reasonable.