1966 Fender Jazz Bass

Check the serial number on the neck plate (or headstock for later models). Fender serial numbers were not strictly sequential — the neck date stamp (penciled on heel) and body date stamp (neck pocket) are more reliable for precise dating. The neck date stamp (penciled on the heel, visible when the neck is removed) is the single most reliable dating method for Fender guitars. Body dates in the neck pocket or under the pickguard corroborate. Pot codes should read 304 (Stackpole) or 140 (CTS) followed by date codes from 1965-1966. Pots should predate the guitar by no more than 12-18 months. The finish should be nitrocellulose lacquer — under UV/blacklight, original nitro fluoresces differently than modern polyester or polyurethane. Nitro finishes check (develop fine cracks) and wear naturally. Refinished guitars often have a too-perfect look. Veneer (round-laminated) rosewood fingerboard — thinner than slab-cut. Round-lam boards are curved on the bottom. Transition era — gold transition logo (some models). Some CBS changes but many pre-CBS features remain. Offset body with two single-coil pickups. Introduced 1960. Stacked concentric knobs for early models. Verify correct control layout for 1966. Check for replaced tuners (original F-stamped tuners should be present), refrets, body routing modifications, and any filled screw holes. Original custom color finishes are verified by examining color in pickup cavities and under the pickguard. Original case adds provenance value.