The Silver Slipper in Edmonton opened in 1967. According to David's post, these were shipped in '73.

Ed is correct, the Silver Slipper is only open during the 10 days of Klondike Days (the big summer fair in Edmonton), so if you count 2005, those chips have been have been in play for 310 days. That's the reason they're still in use, and in relatviely good shape.

As discussed there is an error in the guides and a mis-attribution of the chips.