I got these from the last (I think) owner of H C Edwards (producer of the "H" mold). He lived near me, in Queens county, NYC, and sold them to me before he moved out of NY to the West coast. He had kept them on a leather string in his office.

I had written on my web page, "These chips (all H. C. E. "H" mold) are holed and notched and were the personal chips of the last president of H. C. Edwards, the venerable gambling equipment company that was a major supplier of Nevada casino chips in the 1940's, 50's and 60's. He kept them on a leather string looped through the holes! He just kept this set, one of each; no others. I just have his one of each; you don't have to worry about a box of these popping out of the woodwork. Many of these are one of a kind and were coded after my discovery. (Others, of course, are not so rare, but most are.) This list is a work-in-progress. Not really up to date and finished yet. Except for the holes and notches, the chips are in good condition -- good sharp edges, quite clean, no casino wear and tear. I'll price these when I get the time."
http://www.antiquegamblingchips.com/casino_rare.htm

Robert