Should be able to tell by the axle code. CBV for a 4.10 or CBT for 3.55.
Same location as 69. More info here:
69 Camaro axle codes.
Even the same code, except all the 70 axles have a "C" in front of the 69 two letter code. So a 69 Camaro BV axle became a CBV for 70, used on late Camaros (around Aug. 69) and the 70 Nova.