Here are a couple from the bottom side. The back just overlaps with a large gap. They stuffed this large gap with some sealing compound and then seam sealer over the top of that on the top side. Looks like the factory used a torch to cut the hole but must have followed a strait edge or a machine because they are cut very strait and square. The metal was melted and not sheered. I will get better pictures but these are ones I already have on the computer.