If you go to this link and select your year car you can open up the PDF reader for all the parts in your car. There are pretty decent diagrams.
These fasteners would be in the body section, which is kind of a pain because of all the interior detail parts listed, but I bet you can find them once zeroed into the front fender assy.
Genuine Parts Catalogue - Classic Genuine Parts & Literature - Porsche Classic - Dr. Ing. h.c. F. Porsche AG