That’s a tough question to answer. It depends on how bad your cab is rusted and how perfect you want everything to be. My 66 had damage on eyebrow area ad a little on the inner roof or ceiling area. I was able to bend my own patches & braze them in place. Worked out well for me. Windshield fit well with no leaks. OTOH, all those parts would have been available if I’d chose to replace them. Yes the roof most likely would have had to come off.

1966 C-10 Short Stepside
HiPo
Step-by-step ~ and on-going resto build
in the Project Journals