The reason why the coins were leaving the casino by the truck load was because the melt price of silver had gone up and the coins were worth more than $1.00

From the look of that coin, someone put a lot of work in engraving the date (at least a few seconds to load it an engraving machine).

Do you think a casino would put that much time in defacing a coin (I’ve seen too many drilled chips to think that they would engrave a date on a coin).