I guess it is possible there could have been some variance, but ALL of the original ones I remember in the late 60s and early 70s (not the ones 40 years old that have been waxed) were not shiny. Satin is what I would call them.
Talked to a friend who was a body and paint man for over 40 years and he said they were satin. He said there were several different blends that were used, but there were not what you would call a regular gloss paint. They did have to add flattening agents to the paint. That information was provided to the paint reps from the factory. Now I guess that could explain why there is some variance.
In my opinion, Jim Mattison would be considered an expert and his opinion was stated earlier in this thread.
Buddy and RamAirDave, thanks for the images of the paint in the trunk area.