i was wondering if the lip of the rear glass opening is part of the quarter panel or a separate piece like the the trunk gutters? :confused:

it is a part of the full quarters, at least the originals. I don't have a repro in hand yet , so I haven't cut mine up that far yet. On the convertible, I believe the inner brace that spans over/onto the wheelhouse extends up into that area, not quite sure how far forward yet.
Greg

It is part of the original and repo quarter panels.