I do not know any specific answer, but knowing there are different sizes of POW letter sheets and cards for Italian & German POWs held in the US to write home, I agree with your suspicion that there would be different US-produced forms and editions for writing to prisoners held in Germany.
I have only one of this same form, used very late in the war (in fact so late, by the time it ever got close to Germany, the war was over, if it ever got beyond New York City.) Sent from father to son Harold L Dillon, whose B-17 crashed on November 21, 1944. Dillon survived the war.


