Ok, I am really jealous you live that close. I would hate the traffic and congestion of the area, but there are so many research locations within an hour drive it's absolutely amazing. I plan my vacations every year to go out to that area and research.
On the Garands they have quite a few, but almost all of them are unissued 0-6X rebuilds. They do have some M1C's and M1D's. I remember a couple super early ones but they are not complete or original. If I remember they do have a 2 digit serial number there.
They do have firearms they can tie to famous Marine battles, but unfortunately they do not have any M1's where they know where they served, except for the Makin Garand. I don't remember seeing any that were in an original WWII configuration in the Vault.
We talked a lot of about the Garands because I have the only known M1 Garand that is a battlefield pick up off Iwo Jima in 1945. So they have been interested in putting it on loan to the Museum for an upcoming Iwo Jima display they are planning. I have been thinking about it, because it honestly belongs in the Marine museum on display. But at the same time it does make me a fuzz nervous loaning it out.