Yes, only the one that drops from EC HM Boss can be RE'd. Armoring's pulled from Campaign shells are bound to a particular armor slot (head, legs, chest, etc.) so you cannot learn the schematic by reverse engineering.
If I good understand: only 1 way how to learn for example Advanced Resolve Armoring 26 is drop it from Boss at EC HM and RE it?
It isnīt possible to put it out from Campaign Stalker's Legwraps for example and RE it?