When I had mine replaced on my '95 there were two different kinds of cab corners. One kind was just designed to basicaly cover the rust and not replace it. It just went over the rusted spot and was only 25$. The kind I got was the kind that replaced the entire cab corner and it was about 40$ for each one. I had to cut the old ones out and weild the new ones in and then prime and paint it. Came out good, so I would recomend getting the one that compleatly replaces the old one otherwise the rust will continue to spread. I got mine from Keystone. But if you goto Napa they can get you them from keystone. Thats how I got mine. The only part that It wont come with is the accent that you have on yours and the door. And yes it will completly replace all the rust in the corner. The pic you see of my truck next to my name was taken the day after I fixed the cab corners and rocker pannels.
Good luck!
Good luck!