Make sure you have your bodyman do a complete trial fit of the rear glass, clips, and trim.
I just did that today on mine.
I replaced my left quarter with a Goodmark. The lowest edge curve isn't exact. Now I have to take it everything back off, make a small slit on the curve, slightly push it in, butt weld it, grind it off and re try. I put green tape on first so none of the tar rope sticks to the primered channel. This will allow you to see any edges on the sides too that aren't close enough also you need to re contour.
What happens is that if that curve isn't perfect it kicks the trim out away from the body edge making it look hideous.