As Mark said, those were not used on the 1966 or 67 Coronet door panels. The 66 and 67 front and rear door panels are held in place by wire clips that slide into the backside of the front and rear door panels and push through the aligning holes in the metal door and quarter panel interior sheet metal.

Richard

In this picture, you can see my 1966 Coronet 500's interior door sheet metal with the drivers side door panel removed. The door panel mounting holes are the ones in line where you see the thin line of brown adhesive that holds the plastic moisture guard sheet in place that is located between the sheet metal and the backside of the door panel. (moisture guard plastic is not in place in this picture) These holes are where the wire clips on the backside of the door panel pushes through and expand to hold the door panel in place.



This picture shows the door panel in place and there are no attaching screws in place like the ones you're asking about.



This picture shows the rear door panel in place.



A close up picture of the screw that holds the rear removable quarter panel sheet metal panel in place.



A picture of the wire clips that mount the front and rear door panels on the 1966 and 1967 Dodge and Plymouth B-Body cars to the door and quarter panel sheet metal. The "u" part of the clip slides into the door panel backboards and the the other end of the clip is pushed into the holes in the door and quarter panel sheet metal.