It might be original. Post close-ups of both the tenon and button from a couple angles for a better assessment.
What looks promising in that shot is the button looks radiused, and the diameter of the stem's base looks right in relation to the band (most rep stem makers leave them level because it's much easier & faster to do.)
The odd, too-straight bend could be the result of the pipe being left somewhere hot like a car dashboard, which can soften vulcanite enough that it relaxes & tries to return to its original shape, so ignore that---it doesn't necessarily mean anything.
