If you look BOTH inner and outer roof skins are aviable. Just a comment if you had not looked.
I have two cabs and am cutting steps from one and fixing the one with some minor roof damage. Mine would cost 3k in sheet metal due to an accident and severe bottom rust. Thats why I am cutting up one with a good roof. For me its a $$$$ decision.

Good luck with your whichever way you decide.

Brad