I cut a chunk of the rot out of the outer and started fitting the re-pop piece. It doesn't appear to fit anywhere near correct, for starters it has a flange that I suppose is meant to mirror the lip on the quarter. Problem is that doesn't make sense since the bottom of the wheel house should be the better part of two inches away from the wheel opening. It looks like I'll have to cut the flange off and spot weld the housing to the qtr? 
Any idas on what is going on here? Here it is held in place, the flange makes no sense.
Here's the piece on it's own

Any idas on what is going on here? Here it is held in place, the flange makes no sense.
Here's the piece on it's own