Based on the flat head rivets, the type of aluminum and the stringer still attached on the back side, I would say that it is definitely from an aircraft. The smaller holes evenly spaced apart at the bottom would have attached an additional sheet of aluminum, thus completing the swastika. As for the brush marks on the paint, it is very possible that the markings could have been hand painted on. It was not uncommon to do that during the war. Especially if you were in a remote area and didn’t have a spray gun available. As for the “bullet” holes, they do look a bit square, but we are only guessing they are supposed to be bullet holes. They could very well be from a pick ax that may have been used to dismantle the plane. Let’s not automatically assume that just because it doesn’t match “the norm” that it is a fake.
I think more about Pilot Error’s uncle’s service locations and exactly what his job was in the war could tell us more about the piece.
The pick ax is a good theory! I know, when Watson's "Whizzers" were trying to find as many German jets as they could get their hands on, they had a lot of trouble with GIs who wanted to make sure no NAZI plane would ever darken the sky again!