::) First I will start by saying my knowledge of of the CS cars is limited.

Has anyone noticed differences in original rear quarter panel end caps? I thought it was a difference between Shelby fasbacks and convertibles. I now think it may have been different suppliers or molds???

from what i understand, and i may be wrong, the fastbacks spoilered parts are at a more vertical angle with the flat of the decklid being the origin than the shleby conv. and the california specials. I think I may have read a previous post here with the angle degrees, you may want to check. anyway, i hope that helps.

The supplier was the same, but you are right the molds are different. The difference is in the angle of the trunk meeting the spoiler, like wise for the endcaps. Since the fastback had a long sweeping back window which continued to the trunk lid, that angle needed to be incorporated into the spoiler, hence the differnce in this angle and continuation to the endcaps.
Doug