It is the side supports that fit around the window that would be the problem. If you could make that work, then the rest is just wood.
The back of the bunk is like the back of a dinette table that turns into a bed. The metal bracket also mounts to the window frame. I assume that your front and back windows
are the same as a 4500, but I could be wrong. So, if your side windows are the same width, and the rear window is the same width, then all you would have to do is make a new folding, plywood platform with the supporting oak lumber. Very doable. The cabinets above the dinette get sacrificed. That is where the folded up bunk goes.
I have all the hardware from a 4500 bunk, just like in the ad. I have also got an AutoCAD drawing of the assembly, but I just can't figure out how some of the hardware is used. If you want any measurements, I will be glad to provide them.