+1/2 there Egro.
You are right about the cutout on the regulator assembly, but......
As far as i know the 2834 has not been cloned and a majority of the movement, at least from what i see is ETA.
However the balance cock/ regulator assy is for sure clone. You can even see the finish on the regulator assy is different than the rest of the movement.
I think this is an ETA/clone hybrid here