Another source of info???
I'm not a token collector, but John Kallman (CashCoinCollection.com) is. He only shows $1 regular tokens from Jackpot Junction on his website -- see link below (scroll to bottom of that page). But maybe he knows something and/or may be interested if you are selling.
Just FYI, the GDC logo mintmark on your token stands for GDC Casino Tokens (formerly "Green Duck Corporation"), but they are no longer in business.