Hello Peggy,
Not all $100 tokens were silver. There are many examples of $100 tokens composed of other metals such as the Eldorado Reno $100 from 2000 with mintmark OC, Mirage Las Vegas $100 from 2001 with OC mintmark and the Reno Hilton $100 from 2001 with mintmark RWM come to mind. But the particular Legacy $100 in the ebay listing is silver but unmarked as such.