It's kind of interesting to learn the catalog code for Franklin mint tokens. For the Desert Inn token for example:

DGT-1/C37/P

Means:

Dollar Gaming Token(DGT), first of the dollar token series(1), pure silver(C), Proof strike(P).

It's interesting that for some years and some casinos, there were different metals used for the different 'quality' strikes. Sometimes its obvious in looking at the tokens, but other times you can tell the difference only by weight or by assay. Caesars Palace has several issues in silver that look almost identical to the circulation strikes but are considerably scarcer. Usually FM marked their .925 silver tokens "Sterling", but the pure silver and silver clad versions were always not marked.

Howdy Herz is one dealer who always uses the FM catalog numbers on his tokens for sale. You seldom see them elsewhere, and only the FM and Krause publications have the complete listings.