The 1965 Shelby GT350R Prototype sells for $3.85 million at Mecum Indy 2020 and claims title as the most valuable Mustang in history. The final hammer price on the block reached $3.5 million resulting in a final sale price of $3.85 million including the buyer’s premium. Recognized as the “Flying Mustang,” the first Shelby GT350 “R-Model” ranks not only as the most historically important Shelby Mustang in the world, but it is also arguably the most important Mustang in the history of the marque.