Shelby had such a problem with Ford regarding the CBII that I would be surprised if he built any prototypes using one. I would have to see some good documentation before I would bite on this story.
A CBII with only 7500 miles is rare enough that it would require significant documentation by itself.
It certainly looks nice enough other than the missing front spoiler. But all of the "Shelby" emblems on it are easily available in reproduction, and there are plenty of turbo kits out there for the 302.