There is a common misconception about header fitment in the 68-72 Olds. Some suppliers say their header will not fit a Cutlass Supreme because the engine is offset in the frame 2". This is total B.S. The frame of a Cutlass S and Supreme are pretty much the same for 68-72.
As for your question about body style. The Cutlass for 72 had a "Holiday Coupe" sort of a fastback. This is the body style almost all 442's were. Supreme is a Sedan type body think "notch back" with a wide rear post. The Hurst/Olds for 72 were either this body style or a convertible. Of course a convertible and a 4-door and wagon was also available in the line.
Hope that answers your question.