If the new revision needs less power to hit the same clock speeds as the preceding Phenom II X4 965 BE, then it follows that there might be a little more overclocking headroom with which to play.
To see if this was the case, we tried a simple test: we would increase the Phenom II X4 965's unlocked CPU multiplier using the AMD Overdrive tool. We kept increasing the multiplier in one-half steps until the overclock would crash the system. After it crashed, we would repeat the process, but this time we would increase CPU voltage to 1.5V from stock. We did this test using both revisions of the CPUs, and here are the results:
The new C3 revision Phenom II X4 965 sample we have demonstrated a promising 200 MHz increase in overclockability under identical conditions versus the older C2 sample. Now, we should stress that no two CPUs are identical and there will be discrepancies in overclocking headroom amongst models with identical stepping, so this doesn't necessarily guarantee that your results will mirror ours.
Having said that, a 200 MHz increase at identical voltage certainly seems promising.