Are Sylar and Noah still working together?

After this newest episode, me and my buddy think that there is a possibility that Noah and Sylar are secretly in cahoots.

When Noah unzipped the body-bag, he noticed the knife was still in "Sylar".

Sylar knows that Noah knows thats the only way to "kill" him. And when putting a body in a body bag, the weapon would have been removed before hand. The expression on Noah's face, to me, seemed obvious that he knew it wasn't Sylar. And since Sylar isn't stupid, he knows that sort of thing. So what do you think?