Bill, you are absolutely right. Porsche would sell a race car to just anyone, with the money, of course. Customers made changes to the cars as the season progressed, always trying to find that little edge over the competition. It's why I posted the shot of car number one, first one out of Weissach. I don't have a straight on shot of the nose, but IIRC, there were NACA ducts with large flexible hoses running to the front brake calipers.
The offset in the windshield was to match up with the driver's seat, which was offset due to the required passenger's seat. These were purpose built racecars, but to run FIA events, still had to have passenger seats, spare tires and accommodation for an FIA regulation suitcase. Somewhere along the line they dropped the suitcase reg, but the cars still need passenger seats, and I think spares, except in the pure prototype classes.