One-of-one 1969 Chevrolet Corvette Stingray ZL-1 Convertible heads to auction

A unique 1969 Chevrolet Corvette Stingray ZL-1 Convertible is set to cross the block at an RM Sotheby’s auction in Phoenix, Arizona, on Jan. 16. The Monaco Orange drop-top is the only one of its kind. And it’s one of just two factory-documented ZL-1 Corvettes built for 1969, and the only convertible to get the ZL-1 treatment, an option that added…