Cleaning out the bonnet

I found out today that I have the uber-rare, 1 of 1 1975 Porsche Targa Seville Edition.  Boy if I didn't like this car so much I'd put it on ebay and collect my millions and buy a new project.

I discovered this while removing the last vestiges of the old aftermarket A/C unit that once resided in my car. I really want to have A/C in this car but something tells me this one "Made in the USA for Volkswagen" unit isn't going to be a great starting point.  I'll hang onto it in case I'm wrong and have it tested.