All of the coins that you could see were mostly Morgan and some Peace dollars. All of the silver dollars were housed in a glass case atop the machine. The Riviera Hotel & Casino had one machine with a jackpot of $100,000 in silver dollars until about 6 or 7 years ago.
However, there were still many slot machines in use that dispensed 1c, 5c, 10c, 25c, 50c and even $1 coins. The new owner found bags and bags and bags piled up in a basement, and they contained not only silver dollars but many vintage casino chips as well. The Fitzgerald Hoard wasn't discovered until several years ago when the heirs sold some of his warehouses in the Reno area. The well-known Binion and Fitzgerald Hoards were the accumulations of all of the silver dollars that were removed from the machines at that time and then stored away only to be (nearly) forgotten. The switch from silver dollars to $1 gaming tokens began in the mid-to-late 60's when the government changed to clad coinage.