OP Headstock:
Flat freboard bottom, walnut trussrod plug bisected by fretboard,, TV-logo, binding, dots with non-Fender size/spacing.
Early 70's Jazz headstock:
Curved fretboard bottom, no trussrod plug, TV Logo, binding, blocks.
Late 70's Jazz headstock:
Curved fretboard bottom, bullet trussrod, meets fretboard bottom but barely, late 70's Fender logo w/SN, binding/blocks.
My old TV-logo 73P didn't have a walnut plug either.
looks like a 3rd party neck, or a much later neck that's been worked over? What model/era Jazz neck has a walnut plug? Definitely the 60's basses don't nor the 70's or 80's.