Unless I'm very much mistaken that fellow had those two knives with him at a past CKG (Canadian Knifemakers Guild) Show. I was at Steve Vanderkolff's table at the time he showed them to Steve and got to handle them both. Both knives were mint (I hasten to add that this was nearly a year ago and I have no idea as to the condition of the knives now).
As to the price - I have no idea whatsoever. The "collectability" factor, as Terry points out, can send prices into the stratosphere. If I had $12K to spend all at once on custom knives, I would spend it differently. But then again, I consider myself more of a "knife enthusiast" than a "knife collector". Also, I'm not a huge fan of the ST-23 (heresy, I know!) though I do acknowledge it's place in modern knife history.
Cheers,
Roger