This is the real space shuttle one of three on display around the USA as well as the test shuttle we saw in Washington last trip that now lives in New York.
The exhibition is only temp, they have plans to build a huge exhibition hall and mount the shuttle vertical with the booster rockets attached, should be something worth calling in to see next visit.
There are some incredible videos on You Tube that show the shuttle being transported through the streets of LA from the airport to the science museum, an incredible feat considering the size of the craft.