Got a left cab corner from Summit as above. Drivers rear corner completely cancered out, the wheelwell edge weak, the little interior floor partly gone. The passenger side wasn't as bad, original shape still intact. I didn't need the whole corner piece, so cut what I needed out of it.
At first it seemed like a perfect fit, but after getting a pre-fit done, I realized the shape wasn't really the same. The chevy corner is a fuller, bigger curve, where the original is more like a French curve line, noticeably trimmer and leaner. I kept going with the part, but had to section cut and bend the bottom (lots of jacking, pushing, gentle hammer massaaging) to get the shape right. I'm brazing, not welding