The only 'confirmed way' is to dismantle it and see the actual thing itself...
anyway. u can ask sifu n0th1n about this, he has tested i think 20 dozens
4age gearboxes... hehehe...
btw, your 'new' gearbox is c52 or c56 ar ? managed to find out ?
c56 and c56 with LSD gear ratio exactlt the same???