I think the ruling was that it had to be a faithful recreation of the actual MG36, it couldn't just be a G36 with a bipod.
The list for support and sniper weapons was pretty limited, IIRC.
before you ask, i wasn't there, i just checked out the different rulings on the rules page and heard stuff from people who went.
Sorry man, but I doubt it. It IS a US Military Base, after all.
Actually, during the 2005 Boy Scouts of America Jamboree at For AP Hill, I don't think people of other nationalities were admitted, either (or if they were, there was a fair bit of paperwork).