The prefix Mac vs Mc is not definitive in differentiating Scottish vs. Irish ancestry. For instance McKenzie could just as easily show true Scottish lineage as MacKenzie. While Mac is undoubtedly Scottish, a change to Mc could have happened for a slew of reasons, and none of them related to being Irish, not Scottish. I have done a lot of research on my Scottish relatives McIntyre (aka MacIntyre) and know that it is wrong to be rigid about these things.
Something is not right. This message is just to keep things from messing up down the road