That's a rather odd beast. Aluminium nut, by the look of it. A screw in the middle of the headstock, presumably for a string tree? I'd guess that truss rod access is via the aluminium plate at the bridge end of the neck, but not clear. The body seems to be a refin, if the unrepaired scars under the paint are anything to go by, which makes me wonder if it's a home-carved headstock.