Not necessarly true. From what I have seen/read (including looking at survivors, 69 RRs) the paint color is related to the interior color, not exterior color. Example at Carlisle this year there was a 69 survivor that was teal, with tan interior, and the paint above the door panels was Tan.
Also not that is a bible or anything but the Charger, Road Runner & Super Bee restoration Guide lists Door and Quater color based on the Interior color code combo.....