Originally Posted by Robert_Nash

Maybe a lack of knowledge; maybe misscommunication but as far as I know, the body panels in the 370 coupe and roadster are the same material (they were to save weight but not specifically for the roadster compared to the coupe). I haven't checked the rear quarter panels however but I assume they are the same as well (if not I'll have to order all new autocross numbers for next season!).

I will say that the rear deck lid on the roadster weights practically nothing compared to the hatch on the coupe but I'm sure the missing glass from the rear window is 98% responsible for that (the lack of weight does require a bit of extra force to close the rear deck lid).