"Gene T will probably provide more background on samples as he has lots of them."

I have over 500, but all are notched. Some date to 1966.

"Samples are made to get approval of the customer before volume production."

I don't know how often samples are made before production. I have been involved in 100's of chip orders and only had samples sent 1 time and they were also notched.

"Since sometimes the order is not approved, there can be sample chips that don't match any chip in play."

I have "other" than Nv chips like this but they are notched also.

"Sometimes samples are made on speculation, hoping to get an order."

I doubt a distributor would consider doing this without a customer order.

"Artwork would have been done by the manufacturer in either case."

Most chips are done from art work.

These are typically cancelled by the maker before they leave the source, at least by the major makers who are licensed to sell in Nevada. (T.R. King no longer sells to Nevada casinos).

True.

"I don't know whether you can still buy T.R. King "old chips", but when I first got into this hobby back in '94 I inquired of them and was sent a fax listing all the 'vault chips' they had for sale. There were MANY very scarce obsolete chips listed, all uncirculated, and all uncancelled. Prices seemed high to me at the time (some as high as $100), but I was new and not buying rare chips yet. Today, they seem very cheap [g]."

Unlike most small distributors, TR King actually makes their own chips in their own plant.If you have blanks, it is a small matter to stick an inlay on them.
I know a chipper that has purchased several obsolete UNC chips from TR King.