I wouldn't count on that, because I actually had to update my macbook air just to get the Almighty Thunderbolt Display to work. In fact, my previous MBA (2010 generation, display port)didn't even power the thing up (it's powered exclusively over thunderbolt).
I don't think that's accurate. The thunderbolt displays include a power supply with a magsafe power OUTPUT for charging a mac laptop plugged in to the thunderbolt cable, so it logically follows that they must have their own AC input.
You are right, the monitor does have AC input. Still, it won't even power up unless it's connected to a Thunderbolt port. Believe me, I've learned this the hard way.
