Based my 1967 Build Model year 1968 Coupe (LOS) the Interior cavity (LH) (RH) Door sound deadener was applied AFTER Body color was applied to the door including edge application and "overspray"
When Roger took this car apart he took photos of the door laying on the ground and you can see Clean 'undercoating' thru the door interior access holes.
D.W. should also have some details from his Red Car preservations.
JIM