Agreed that that would generally be the case, especially for experienced EK collectors. But one must think that the right marked ring on a combo of known fame and core could cause some confusion. Imagine if it was a known core (from one maker) and a known frame (from another) topped with a stamped ring from the opposite company one would expect. I would guess in certain situations, where the combo of parts has been witnessed but no conclusion of maker/assembler has been determined, it could make for a debate not necessarily had before.