The only platinum FM gaming token I know about was for Harveys and there was only one made. I think you may be mistaken on this one. Is it marked Pt on the token somewhere?

Be aware that there are 1967 $5 tokens in existence that don't have the word STERLING on them. They are usually silver clad specimens. I am away from home and don't have my references to see if Mint has one of these listed.