Wheel House Question

I axed this question up in the Members Restorations forum and didn't get any hits.............
I noticed this when I replaced the quarter on the passenger side as well and can't figure out a reason for it..............the outer wheel house has two slices, at a right angle to the edge of the pinch weld flange at the 10 and 2 o"clock positions. Anyone have an idea why they are there? Any reason why I shouldn't weld 'em up? L8r