selling you a 1/4 panel would be no problem, IF the part is actually available anymore.. a replacement frame or a partial frame MIGHT be a problem, but i really don't think it would. the restricted sales parts i am talking about contain high or ultra high strength steel. to install these parts properly you usually need a squeeze they resistant spot welder or a silicon bronze mig-braze welder. most full frame truck frames are made out of regular strength steel.

at least by me. with the prices of used southern rust free boxes these days. it might be better to just buy a new salvage box over repairing the damaged 1/4 panel one. our shop did this on the last 3 box sides that needed to be replaced.