Authenticity and modification checklists

Before buying, verify at least:

1. plausible model and variant;
2. consistency of serial and other identifiers;
3. date codes and major components;
4. finish, structure and evidence of work;
5. replaced or modified parts;
6. available documentation and provenance;
7. functional condition and service history;
8. accessories and retained original parts;
9. comparables with similar originality;
10. points requiring specialist verification.

If a point supporting a large part of the value remains uncertain, include that uncertainty in the decision and the price.

Before a modification, major repair or restoration, ask:

• what is the actual problem or objective?
• is the intervention necessary or simply desired?
• is there a reversible solution?
• will it require drilling, routing, cutting or other permanent changes?
• which original parts will be removed?
• can they be retained and identified?
• is specialist work required?
• have you photographed the starting condition?
• will you receive a list of work and replaced parts?
• how will the correct description of the item change after the intervention?

The guiding principle is simple: improve usability without unnecessarily losing information.