Very interesting! Believe it or not, you found the car. "Your" convertible has the same license plate as "my" coupe. I think it is time to reveal the whereabouts of the puzzle picture. It was taken during the Liège-Rome-Liège rallye, supposedly in Liège at the start of the 1938 edition. It seems as if the puzzle coupe was converted into the 1939 Alpenfahrt convertible.
Do you have further information about the technical base of this Hanomag rallye special? Rekord like the other coupe?