It's been all but confirmed the beauty cars(cars seen close up) were painted 1975 Corvette Flame Red, GM code 70. I remember reading an article that stated when they scanned the trunk lid it matched Corvette Flame Red. Even a scan of old paint won't give accurate results. Reds, yellows and oranges tend to change more than other colors over time. They did use other orange colors on the stunt cars mostly to save money and would often mix leftovers to make enough to paint a car.
Some people think Hemi Orange was used but it wasn't. Hemi Orange is a 1969 Dodge Charger color but it's a very dark red-orange and almost always photographs red. Hemi Orange does have a light metallic in it too.
1975 Corvette Flame Red is the main color of the General Lee.