How exactly do Fleetside bedsides come apart?

[Ziptar]

I am getting ready to strip the bed parts off the 85 to swap onto the 79. The 85 has a perfect Bed floor, Fender wells, inner bedisdes, end bed panel, and tailgate posts but the outer bedsides are rusted through. The 85 had a cap on it all it's life until I got it.

The 79 has great outer bedsides but, the Floor, The fender Wells, and the inner bedside behind the drivers wheel well to the tailgate post is rusted through in spots up to in inch from the bed floor from years of having a plastic bedliner installed. The Tailgate posts and the end bed panel are OK but not as nice as the 85.

Does the outer bedside skin seperate from the inner bedside? can I just swap the outer skins on the 79 to the 85 bed? It looks like on the parts blow up at LMC that the inner and outer bedsides are all one unit.