Gaeten le Grand,
Mon vieux, the petit red circle may be the earth point for refueling wing tanks. the other earth point was behind the main fuselage (red) fuel cap. in other theatres the earth point was painted dark (black striped) yellow. If translating a B&W photo, are you sure you have the right color ? take my comments as suggestions - i cannot comment authoritatively on this ! Try me on A-20Gs, especially dash 20 series (my expertise). btw, good work
Michael Claringbould