A team of Marines showing up is not very likely; while most Norwegians don't care too much about Edward Snowden (Edward who?), soldiers of a foreign power executing an operation on Norwegian soil would create an outrage that would definitely topple our government. For starters.
I really can't see our (US-friendly) government allowing such an operation, knowing full well it will make them look terribly bad and in all likelihood cost them their jobs AND their reputation.
And the US deploying Marines in Norway without the government's explicit consent? That is called an invasion, and not likely to go down well, either.