E-Bodies always had the door frame codes 000 because they were pillar-less.
Just to further clarify your statement, 1970 Cudas & Barracudas "always had the door frame codes 000 because" their interior door frames were completely covered with a door molded panel. There were no interior paint code options for the upper panels like you would find on an A or B Body vehicle. Our project also has interior door panels that completely cover the (interior) door frames. Again, the 000 had nothing to do with the "pillars" or the outside window frames of a vehicle.