I don't doubt it's the real time engine. But all the Uncharted games early trailers were too, but the final games always ended up looking different. We see it all the time with trailers. A lot of time the video trailers are "in-engine," but not "in-game," instead rendered offline, resulting in super smooth details that don't exactly look the same when the game ships. The Uncharted 3 E3 trailer looks better than the final game.
I'm sure it will end up looking slightly better than Uncharted 3 or at least more refined. But don't get too hyped about the trailer, it could even be a target of what they hope to achieve. That happens all the time before they start adding in dynamic lighting, AI, scripted animations, etc. It all taxes the hardware and cuts have to be made for gameplay's sake.
