This is the current info about the "BTTF" car in question taken from the current Wiki entry for G. Barris, followed by a link to that page:
Back to the Future controversy
Over a decade after the release of Back to the Future Part III, one of the DeLorean time machine stunt cars used in the film was sent to Barris for restoration purposes to be put on display at the Petersen Auto Museum in Los Angeles. The car was returned to Universal Studios in 2003. Barris later purchased a stock DeLorean and converted it into a replica of the Back to the Future DeLorean, which he used to promote himself and his company. While Barris never officially stated that he had anything to do with the Back to the Future films, he did like to indulge in stating that he had built a Back to the Future DeLorean, but never disclosed that it was a replica car.
In 2007, Universal Studios officials sent Barris a cease and desist order demanding that he never again make misrepresentations regarding any involvement with the Back to the Future films. They called upon Barris to remove images of the flying DeLorean from his company's website and restrict his display of replicas of the gull-wing car used by Michael J. Fox in the popular 1985 movie and its sequels. Back to the Future writer/producer Bob Gale went on record stating that "George Barris had absolutely nothing to do with the design or construction of the DeLorean time travel vehicle.” The DeLorean was designed on paper by Ron Cobb and Andrew Probert, and it was built under the supervision of special effects supervisor Kevin Pike and construction coordinator Michael Scheffe."
https://en.wikipedia.org/wiki/George...to_customizer)