Auto Metal Direct Fitment Issues?

I purchased an Inner fender extension for my 69' dart,the L shaped part that attaches to the trunk, and then out and down to the outer quarter panel. It was of very high quality, and every bit as good as the original.
That seems to be the general consensus. They had the official Mopar seal of approval on them even. I haven't tried every panel, but am afraid to take that risk - plus I can't remove much more structure at the moment with the rocker already out.