If your dates are correct, these blanks were all made by Burt Co. for Bud Jones.
BJ could have had large quantities of these on hand at any time for the purposes of hot stamping (which they did themselves).

IMO your chips either comprise salesmens samples, or came from the BJ estate. When Borland bought the BJ estate he would have obtained thousands and thousands of blanks. He didnt use them all. When Borland died they passed to Jerry Wall. When Jerry sold his stock there were many still available.

I have around 150 different ones in my collection. I purchased most of them 5 months ago in a single lot. I got them from someone who bought part of Jerry's stock. They were still in the Burt Co boxes they were supplied in 30 years ago.