VWrabbit317, By early 80's pickups I am going to assume you are talking about the 80-81 models. The 1980 version had the smaller 1.5 l engine in it and somewhere during the middle model year they started switching to the 1.6 l that went on forever. But you can insert all kinds of the engines in them clear to the 1.9 l if you want.
I think the rust issues hit all model years. The way they were built just has water pooling near the A pillar supports so you see that spot just below the windshield develop. The strut towers as just a very wet environment and the pinched metal and struts just keep it there unless you live in AZ or NM.
The ceramic fuse box was in the very early Pickups but anything past the mid 1981's is plastic. You can swap them but that is a major headache laying down all day long to do it. But if you are good with wire and such it shouldn't bother you to do that.
I think that late Westy front end goes on most all of the trucks with square headlights. Is that the one you are talking about? Putting round lights in place of them can also be done but you might have trouble finding them.
Build quality was good for most all of the VW's but the ownership and maintenance is what is going to give you a decent PU. Think what nearly 40 years does to anything that is left out in the weather and abused. Or worse, left in a field, on flat tires, open to mice, and the rain. Just don't fair well in those conditions. Yet, those are the ones you may have to choose from for a restore. If that is the case, maybe working yours back to like new might be an option.