I'm not proficient in hardware, but what I do know is that the processor is one chip that includes the WiFi, radio chip (in some models the LTE chip as well), and the core processors along with the GPU. I'm not sure about the terminology, but it may be what you call the IC. Someone correct me if I'm wrong. If that is correct then it is normal to have a different mac address since the WiFi chip was also replaced.
Rooting Samsung S2 - bricked phone