In 1993 The old Camaro Club published a listing of Coupes -vs- Convertibles in their magazine "The Camaro Enthusiast". In it, they stated that of the 4575 L78 Camaro's built in 1968, 329 (plus or minus .1 percent) were convertibles. Just HOW they arrived at this numbers is unknown, but I would say it's probably in the ball park. Even if it's way off, the L78 Convertible is a rare car.
Ed