Quick answer

A fake Vacheron Constantin Traditionnelle Perpetual Calendar is a counterfeit watch. It copies the dial layout of the real reference but uses a different case metal, movement, and finish. The real reference 43175 has a 38 mm 18k gold case and a caliber 1120 QP with a Geneva Seal. Fakes use gold-plated brass and a generic calendar module. Price is the first signal. Genuine models trade from $50,000 to $100,000 on the secondary market. Fakes sell for $200 to $800.

1. Weight and case metal

An 18k gold case head weighs about 80 g to 100 g. A plated brass fake often weighs 50 g to 65 g. Gold does not flake. Brass shows wear at lug edges and the crown. Look at the caseback screws. Real screws sit flush. Fake screws sit high or strip.

2. Movement and caseback

The real watch has a sapphire display back. The 1120 QP rotor is solid gold with Geneva stripes and perlage. Fake rotors are steel or brass. There is no Geneva Seal on a fake. The 1120 QP runs at 19,800 vph and has a 40-hour power reserve. A timegrapher reading of 21,600 vph or 28,800 vph points to a fake. The balance wheel on a fake often has no adjustment screws.

3. Dial and calendar

Subdials: day at 9, date at 3, month at 12, moon phase at 6. The moon phase disc runs a 29.5-day cycle. A fake may use a 24-hour disc or a printed moon. The leap year indicator on a fake may skip years. Check the font. Real dials use thin, sharp printing. Fake printing is thick or blurry. The date hand on a fake may not align with the date window.

4. Papers, price, seller

Real watches come with a Certificate of Origin, a service booklet, and a wooden box. Fakes ship with a photocopied card. Ask for a service invoice from Vacheron Constantin. Call the boutique with the case number. A price below $40,000 for a gold perpetual calendar is a red flag. Counterfeit watch sales are illegal in the US under 18 U.S.C. 2320. The FBI and Swiss customs seize thousands of counterfeit watches each year.

What to do

Ask for high-resolution photos of the caseback, movement, and papers. Meet at a Vacheron Constantin boutique or a certified watchmaker. Pay with a method that allows a chargeback. If the seller refuses a movement inspection, walk away.