Tokens are made with all kinds of mixed metals... Most $1 coins from the same manufacturer are roughly the same. In our market we had 3 casinos that used GDC (Green Duck) tokens and we got all 3 casinos tokens all the time. When our 2 casinos went to Osborne Coinage the other properity still had Green Duck tokens, they no longer worked, because the Osborne tokens had a different metallic composition.