I posted this scan in a post about Fort McDowell. I have had a request to post what I know about this token. So here goes.
This is what I know about this token. The way I heard the story is. When the Arizona casinos first opened there was a maximum bet limit of $8. In ordered to allow the slot players to loose the maximum on a pull the Fort came up with the idea of $4 tokens. Four $2 tokens took too much time I guess. The machines are now gone or in some part of the casino I do not frequent. I have never seen any other casino use a $4 token.
If anyone has more information any correction is welcome.