Antics with semantics.
A "BE" coded rear end does not have a VIN stamped on it, and all COPO Camaros had "BE" stamped rear ends. If the car in question has a "BE" stamped rear end, it is an "original" COPO rear end. There are other restored COPO Camaros that have "BE" stamped rears from cars that were scraped, and are claimed to be "correct".
Parts is parts.
In one sense they are, because the "BE" was a unique code number, but since there is no VIN involved, is it any different than a carb or distributor that has the correct code?