Guitars and basses
Originality of woods, finishes, pickups, electronics, hardware, neck and structural interventions.
On guitars and basses, inspect finish, woods, joints, neck, headstock and cavities separately.
Scratches and wear may be consistent with age; refinishing, structural repairs or routing instead change material and configuration. Look for colour differences, overspray, added holes, enlarged cavities and signs of glue work or breaks.
Do not conclude from one photograph alone: finishes can age unevenly and older repairs may be difficult to detect.
For important items, photograph uncertain areas before disassembly and limit disassembly to what you can do safely.
Pickups, potentiometers, capacitors, switches and wiring can provide many clues. Compare codes, materials, wire colours, soldering style and layout with documented examples.
A disturbed solder joint may indicate service or replacement, but it does not by itself explain when or why. Conversely, old-looking solder does not automatically authenticate a component.
Record which parts are consistent, which are known replacements and which cannot be verified without invasive work.
Avoid desoldering components merely to “check more closely” when the operation could destroy useful historical evidence.
Tuners, bridges, saddles, pickguards, knobs and strap buttons are often replaced because of wear or preference.
Check whether the replacement uses existing holes, whether impressions from earlier hardware remain and whether removed parts have been retained. A reversible upgrade with the original hardware included is different from a change requiring new drilling or machining.
Also consider correct function: a damaged original component may have documentary value without being the best choice for daily use.
Always describe what is fitted now and what is supplied separately.