It's crazy how hard it is to find this info. Couldn't find it anywhere after a few mins searching google. Nothing listed on the Bose site or the Mazda USA site.
I think on the 2nd gen, the center dash speaker has a tweeter on either side of it (plus the other two speakers on the dash). So there are actually 5 in the dash, 2 in the front doors, 2 in the rear doors, 2 in the 3rd row and the sub. I don't know for sure though.