Can they burn a Koran too?
Sure, but they better check local ordinances against open fires to make sure it's properly contained, and they better have a receipt for the Koran.
But I think that would just be counterproductive. What they are planning is pretty ballsy, but it's directed at Osama, not at Islam's Holy Book. I predict that local muslims would get a lot more upset over that than hanging Osama in effigy.
And if I'm wrong about that, and they're all Al Quaeda sympathizers, then why bother burning the Koran? Torch the f*ckin' mosque.