Re: U-2
I don't know what they're currently displaying, but when I was there in 1988 the U-2 was real. It was an early model, probably a U-2C. The C model is a lot smaller than the ER-2s they flew most recently. It looks pretty flimsy, too, but that was because the weight was kept to an absolute minimum to get as high as possible. It's pretty common for display aircraft to be stripped of usable equipment (engines, instruments, etc) before being put out to pasture. That may be why it appears to be a mockup.
It's also possible that the one I saw as this one, currently on display at the Museum of Aviation in Georgia.