From the manual: "To adjust the truss rod, use either a large Phillips or flathead screwdriver (for most vintage style basses), or the hex wrench supplied with your bass (for modern basses). Note that for vintage-style basses with the truss rod adjustment at the neck heel, you must remove the strings and loosen the neck mounting screws and/or remove the pickguard to gain access to the truss rod adjustment nut"
You may have access by removing just the pickguard but don't count on it. I would recommend removing the pickguard & neck and carve (...gotta love me some Dremel!) an access for future adjustments. It may alter authenticity but it's a RI for cryin' out loud.
Riis