67-72 body part interchangability?

[DarkFlounder]

When I got my 72 GMC long bed 4x4, I already knew I was going to have to outright replace the bed. Decades of hauling firewood have beaten it into submission. But I thought the cab was salvagable. Some rocker and floorboard rust, but nothing unrepairable.

But I've been giving thought to finding a reasonably straight and rust-free cab and prepping/restoring it off the truck.

So, my question is, how interchangable are 67-72 cabs, beds and doors? What are the differences across those 5 years?

I don't need to be original to the 72, but (for example) will a 67 cab look wrong next to a 72 bed.