Lets see if you can make sense of these pictures. I dont have any good original panels to show, but you can see the inner structure is radically different.

They left out re-enforcements along the bottom and both sides and they did not carry the upper brace to the edges. The upper side holes are not drilled large enough. The curves are not quite right and required a shrinker to fine tune them. The panel also had a torsional oil can where it only liked to be twisted in one way or the other. The upper edge should should also have a slight arc to it but the repro is flat. The panel is also not wide enough and you can see the corners of the original brace pushing the sides out.

In the last two pictures I show the repro sheet metal skin with all the original doublers and the brace being laid in position.