Chipco was not the only Co to notch chips for salesmen. Paulson did the same for years.
NV Gaming put a stop to this around 2003 after a $500 notched got cashed in at a Biloxi casino.

Salesmen sample chips have been sold into the hobby. I bought several 1,000 from a Chipco salesman in 2001. Spragg has been showing a large salesman's sample chip collection the last few weeks. That one is pre 2001 or so.

NV Casino's can no longer notch chips for keychains, etc. NV Gaming is now requiring destruction of recalled chips.
Distributors will still make a limited number of notched as samples for the buyer to see, prior to running a new rack of chips.

We will be seeing a lot less of newer notched as time goes on.