I would think he would call 911 on anyone, no matter what race if something looked suspect and not just on someone of AA descent.
I think the point here is that no white teenagers EVER looked suspicious to GZ, as far as we know. This information will probably come out as it is investigated.
And I believe that neither would Trayvon that night had he been white and dressed differently. Oh, and maybe hung his head, called GZ sir, and ran all the way straight home after being "suspected".