Good Morning Allan,
Many of the old Golden Nugget chips were cancelled by drilling, hence the hole. The ones that are also "sheared" or "clipped" were taken out of a key ring they were sold in. The Trading Post in downtown Las Vegas sold MANY of these key chains in the late 60's early 70's. The key chains contained the old issue Golden Nugget chips as well as others from downtown casinos. Hope this helps.
Best, Jim