Hi Gene: how about the 50c dice/aces mould on the Vegas chip site listed the date of the chip as 1968. Edmonton Slipper I presume would be sure of when they received the chips. Right! Also looking into casino chips in Manitoba dice/aces mould. Monte Carlo, AGA Royale and Manisphere plus Imperial Amusements. All earlier dates than you mention. Better check on Burt Co. records.
Yours in chip collecting. Not interested in selling chips. Rather trade. Thank you.