71 long beds

[stich626]

Hello,
looking at my 71 bed , it's fairly rot free, but has rust.. not bad, but..
this thing looks like it's all bolted together,, but because it was a texas truck it's got no where near the rust/rot that a rustbelt would, but is got bondo from it being a truck and the dents of 30 years of that,,
anyways, I can't really tell if there is any welds from the factory..
as I redo this bed, and sand the metal floor, it seem like a good time to clean the light rust out of the seams, easy enough while unbolted..
but because it's a bed and will see the sun, what seam sealer (if any) should be used after it's bolted backtogether..
or will the paint systems "sealer" and etch primer be enough..
would a rubberized gasket help.. (think the poured rubber they put between concrete slabs) or a thin bead of rtv or am i over thinking this..
also, does anyone make long bed sides, if these are deamed to far gone,
unlikely unless there is funk under the 4 paint jobs..
just an option..
found short bed and flare side bed sides..
but not long beds (not a longhorn)
thanks..