Not sure about the Science Museum, but the VMFA is 100% ok to carry. I OC there whenever my girlfriend drags me along to go with her. Here's what usually happens:
The security ninjas ask me to leave. I tell them no. They try to get my name (the guy actually pulled out a notepad and a pen- I had to stop myself from laughing). I refuse. They return to their secret holes in the wall. They know that carry is legal/preempted there, and they can't do anything about it, but they still try.