There are some who feel the 'bring back' papers add to the value of the pistol. I don't agree, but if you are planning a display or a diorama they would be a nice addition.
I've always thought it would be amusing to do a Wehrmacht version of the 'bring back' papers [in German], describing an M1911A1 brought home [to Germany] by a returning German soldier.
I spent two weeks in Germany back in the 80's, at a Bundeswehr Luftwaffe air base. We had elderly German veterans as bus drivers. They all had souvenirs to sell, they all had stories, too - the most common one was to tell that they had fought the Russians, the French, and the British...but none had ever fought the Americans!
Ah, well. I drive a Nissan.