Your numbers are a little off . . .
The option was made available on the Cutlass hardtop, Cutlass S sport coupe, Cutlass S hardtop, and Cutlass Supreme ragtop. So those 920 (assuming that's the right answer for non-ragtops) were both hardtops and post coupes.
Going from memory, 17 were Cutlass hardtops and 19 were Cutlass S sport coupes. The rest were Cutlass S hardtops.
PS> You should know better!
