This prototype was made in 1965 for the Horshu Casino in Jackpot but isn't dated. Made by Osborne using a Goldine finish. I don't think any of the Goldine tokens were made for casino use, but the Silveen finish was certainly used for both $1 and 50c tokens at several casinos. Both sides are shown but only difference seems to be the two horseshoes and the two raised diamond designs. Over 50 years old.

These are scarce. O'Neal catalog 1046. You can have one for $55 delivered in USA. Looks unused to me.