Here are some pics I got before painting mine. Barry was one of the people who helped me, so this might be from him. (So many great people helped me out, that I can't even remember who all I talked to).
But this is an original stripe from the factory (Yes, someone ordered this color combination)
Despite all the measuring/calculating/interpreting, we really used these pictures to 'eyeball' the stripe on my car. Especially the first picture below - You can see how the stripe sort of gently 'bends' along the quarter, and does not come to the front edge of that bumper notch. My painter and I used this picture as the guide. Every car was probably different (as they were back then), but this one just looked 'right' to me, and it is original.
Hope this helps...If you still have questions, just let us know.
-Tom