Yes they are authentic! Besides the 4 tokens per card they also sell in binders. The inside cover of the binder tells the whole story for that particular year. Dan Wickett's excellent website includes the information that is contained in the binder. There are also various FM publications that tell mintage and such.

The short story is that the casinos needed to private mint slot tokens because the price of silver made silver dollars worth more than $1. FM was the major company hired to manufacturer tokens. In addition to the tokens destined for circulation, they made some proof/proof-like sets.

I've got extras to sell if you are interested.