Looking close at the base of the glass I would venture to say it's an original lamp. See the darkening where the glass meets the base. I don't remember seeing that on newer lamps. Just a guess.
Ahh, the later faux Westinghouse lamps returned to the sqaured off BT-28 shaoe. But they were no longer cleartop. I've never seen a 400w faux Westinghouse cleartop before lol.
Ah they're using the "rel" BT shape again? Nice! It's too bad that BT25s are non-existant. The other BT lamps seem to have at least remained somewhat in production but the BT25s really got killed off for good.