I'm not sure, It depends on the bus speed. I'd say the 1.33 GHz, because it is designed to run at higher speeds. If the 1.2 is a part of the axia range, while the 1.3 isn't, I'd say the 1.2.
But if the 1.3 GHz is using a 100 MHz bus, then it is reaching the higher multipliers. You'll need to pump up the bus speed to overclock that.
<i><b><font color=red>"2 is not equal to 3, not even for large values of 2"</font color=red></b></i>