I handled one at a gun shop in Twin Falls around 2006. It was the standard USIBP marked 4" .38 Special, unmolested from its original configuration. I had read Charlie Askins personally sighted all of these guns in, and had bent the front sights if needed, as noted above. This one must have shot to Charlie's satisfaction as it was unbent.
The gun shop owner knew what it was and wanted a grand for it, if I remember right. I didn't have the cash, so I brought in some trade bait. I had a Colt New Frontier .45, a Winchester Model 52, and a no-dash Model 19 on his counter, and he was still shaking his head. In a rare moment of gun-buying clarity I came to my senses, gathered up my guns, and went home.
I love Colt New Services, I love .38 Specials, and I got a kick out of Askin's book, but I'm glad I passed. Of course, all the guns I mentioned above have since been traded off anyway for something else I had to have.
I think the example I saw would go for $1500 to $2000 or so nowadays.