Great find. I also have a rare Buick. I purchased it in 2007 from the original owner with 12,000 actual miles on it. It is a 79 Century Turbo Coupe. It is a highly optioned car and all original with except for the tires, battery, belts and exhaust. The owner gave me a letter from Buick that stated that in 1979, Buick built a total of 61 Century Turbo Coupes. I had tried to independently verify this, but haven't had any luck. I contacted both Sloan/Longway and GM Archive but they said that information was not available. I would be interested in how you obtained your information.