[sdhotwn]

The CS roof is a structural member, otherwise it couldn't contribute to body stiffness. Therefore it is part of the body/chassis. Not sure where the confusion is.

(maybe confusion is around the mixed terms. Body or chassis is usually referring to structural load bearing, torsional rigidity, or stressed member portions of the car. The "frame" in the old days or on portions of trucks, monocoque, tube chassis, or unibody depending on construction. "Bodywork" refers to covering panels - fenders, hoods, trunk lids, doors, etc.)