What is the difference (in terms of speaker configuration) between the premium sound and stock? Does premium sound support 9 ch surround or 7? Mine says its 7.1 surround sound.

I have one set on the A pillar (that would be one each side, so two), one set on front doors (one each so two total) have two sets on rear doors (four in total) and four on the C pillars (two on each side) and that totals to 12 speakers and I;m also assuming i have two subwoofers under my front seats. I do not have the 6 cd changer in the glove box. Is that the premium sound configuration? I'm supposed to have it but some how i doubt that I do.