Most likely used on both, knowing Henry Ford. Back then paint colors were fairly constant Red was red, Carmine a bit deeper, maroon was maroon or dark maroon. Paint makers didn't expand to wild or nuanced shades until the 30's.
I think the suppliers of finish products could have made about anything a manufacturer wanted. Automobile manufacturers used what they felt they could sell. Wild was likely not something they would have considered but they did use nuance shades of colors on the Model A cars.
In 1926 and 27 Ford was trying to find ways to sell a car that was rapidly becoming less popular so they tried all sorts of things to keep sales from faltering. Royal Maroon was one of the three colors they chose to use for late 1926 and early 1927 production. All black was old hat and the model T was as well so they shut down production in late May of 1927 to concentrate on the New Ford model A.