The 50c dice/aces mould chip used exclusively by the Silver Slipper in Las Vegas has the date of use as 1968 on Paul Hegge's list of Nevada chips.
The person in the know at the casino in Edmonton, Canada told me they received the $1 and $5 dice/aces mould Bud Jones chips in early 1968. I would say the mould existed before early 1973 in this case. MOST chips of today have the city printed on the casino chip. I was advised by a person of high regard in the chip world of the law the US government passed that casino chips must have the city of origin on the chip as of 1969. The Silver Slipper chips did not. You do the math. Happy Chipping.