I have sold several sets of these for exactly what you describe. You end up replacing the inside panel along the original lines and then having a very small patch on the outside just a bit bigger than the actual window.
https://www.flickr.com/photos/advance-design_parts_co/8129345505/in/album-72157631868452754/
https://www.flickr.com/photos/advance-design_parts_co/8129371322/in/album-72157631868452754/
The benefit over the Dynacorn entire panel replacement or your donor is you don't lose cab integrity and end up having to brace and compensate. You also can work one side at a time.
I have a detailed set of instructions I provide with the sets, I can send you a copy if you PM me.