I have a genuine factory "early whale tail" for sale, from a 76-77 3.0 turbo (with A/C).
It is of metal/fiberglass construction and the central brace is stamped with the part number (930.512.010.01). The tail is in excellent condition, with no issues identified.
It comes complete with the factory rubber lip (911.512.019.00), which is in amazing condition. The color, texture and shape/curvature is superb (I tried to take photos from many angles to illustrate this - there are so many mistreated lips out there which look wavy).
It also comes with both factory grilles. The auxiliary grille is factory, not a big grille that has been cut up to fit in the recess. It includes the "T-bolts" for the auxiliary grille, but not the main grille.
$4,000 plus shipping and Paypal fees. Also available for collection in San Diego, CA.