Although not official just yet...Conan's bridge burning statement pretty much confirms it.
I suspect they will use Leno's current set (with a few modifications) at NBC Burbank. Leno had his old Tonight Show set for 10 years, and there is really no need to go back setwise. The Universal Studios set will be abandoned. Format will go back to the way it was, but I suspect the Green Car Challenge will remain.
Leno will also have an airtight contract. I suspect if NBC tries to evict him again, they will owe him half a billion dollars.