I don't know the answer, but one fun fact is, I seem to recall, and likely from my copy of Last Onslaught, that it was available for sale to the general public before the fibreglass Corvette was. Corvette's first owners were hand picked celebrities of one sort or another, and they got them before the Darrin was available. If you weren't a Marilyn Monroe, a Dwight D Eisenhower, or a Mickey Mantle type of personage, you were out of luck (just as examples, I don't know who got them) So, the Darrin was the first North American fibreglass sports car from a car manufacturer sold to the public.