My cousin received her MtDna results back. My results would not be the same, as my father and her mother were first cousins. Anyway, as I understand it, this test gives results from many thousands of years ago. She said French and German ancestry showed up, but no british isles. Her maternal line is this:
Mother born USA
Grandmother born Canada
Great Grandmother born Canada, Irish father
Great Great Grandmother born Unknown around 1800, but previously thought to probably be Ireland.

So, with my cousins results, is it fair to say that the unknown great great grandma was not born in Ireland, or is the test not specific enough that recently.