iv ebeen staring at this pic, and, it looks like the grain that dosent match up is from carving into the wood; like bookmatching, then taking off too much and losing the carbon copy;
id almost say he slapped a piece fingerboard thick across the whole length the sliced out the drop in the headstock; and if not im gonna!
its good practise to use hard film finishes on 'spongy' woods, but isnt always nesescarry ;as far as a bolt on;
id do the same thing i do with swamp ash;route a deeper square in the neck pocket(not visible to outside) a few mm inside the perimeter of the pocket, and inlay something hard like rosewood or ebony, which is like a hidden neck screw plate, i know ash is denser, but the same theory could be relevant, maybe a lil thicker of support