GM is GM, there's no way around that. They wouldn't label it GM if it wasn't the FINAL shipping version. If there were still bugs that needed to be fixed they wouldn't label it GM. Software builds tend to hit GM status sometimes months before they're released. All the other fixes that get worked on get pushed out in the first update. Leopard went GM about a month before retail. Windows Vista was GM about 4 months before retail (the same version available to MSDN subscribers what was the retail build months later). I think the non-developers have a misconception of what it is. GM means final and that's that. When software is "done" it gets the GM label. What will be available on iTunes Wednesday will be the same build number.
When is software ever "done"?
Also, I'm already looking forward to 3.0.1 because 3.0 is kinda crappy right now.