You're 2% light which is OK since you can add lead tape and an OG to bring it to what you like. If the frame came in unstrung at 322 grams, then you would have a lot more trouble modifying it. BTW, this is Wilson QC we're talking about and yes, 6 grams may seem excessive, they would pass anything within 3-4%.
I have two, one is noticeably heavier which I prefer. But I have no idea how much they each actually weigh. A tennis friend of mine is also having the same experience, though he prefers the lighter one.