Originally casinos would drill old chips and sell them on key rings. Then in the 80's gaming regulations across the country (into the 90's) made it mandatory for manufacturers to submit a complete set of notched chips for every proposed new rack. One set for gaming, one set for the manufacturer, occassionaly a set to the casino and one set for central credit. Quite often casino's didn't want a notched set as they had the real ones. Notched samples from the manufacture would be in mint condition for sure.

Also, any returns, defects, errors and counterfeits were normaly returned to the manufacturer to be ground up. sometimes the manufactures would hold on to these anomalies but would notch them.

I'm not sure of the value either but would think that a complete notched set ($1 through say $5,000) should collect some interest.