Short answer

A fake IW329087 is a copy of an IWC Pilot's Watch from the IW3290xx reference block. That block holds Mark XVIII models. The genuine watch uses a 40 mm steel case, a sapphire crystal, and caliber 35111 with a 42 hour power reserve. Water resistance is 6 bar. Replicas copy the dial layout and the case size. They differ in case finishing, movement, dial print, and price.

The string IW329087 does not match a published IWC catalog page in the sources checked for this guide. Confirm the number with IWC before you buy or sell. A number that fails that check is a warning sign by itself.

Reference number structure

IWC reference numbers start with IW and carry six digits. The first four digits point to a model family. IW3290 is the Pilot's Watch Mark XVIII group. The last two digits mark the variant, such as dial color, strap, or market. Buyers who search a full seven-character number should expect most results to be resale listings, not factory pages.

Genuine specs to compare

  • Case: 40.0 mm across the bezel, 10.8 mm thick, stainless steel
  • Movement: caliber 35111, automatic, 25 jewels, 28,800 vph, 42 hour reserve
  • Crystal: sapphire with anti-reflective coating on both faces
  • Water resistance: 6 bar, about 60 m
  • Dial: matte black, white printed numerals, date window at 3 o'clock

Six points to check on a replica

  1. Caseback engraving. Genuine text cuts deep with sharp walls. Replica text sits shallow on a polished field.
  2. Date wheel. Genuine digits center in the window with an even font. Replicas show off-center print and a wider numeral.
  3. Crown. Genuine crowns carry the IWC logo in relief with crisp edges.
  4. Crystal tint. Genuine sapphire shows a blue reflection from two-sided coating. Many replicas carry coating on one face only.
  5. Lume. Genuine numerals hold an even fill line. Replicas show overflow at the numeral edges.
  6. Movement. Replicas of this reference carry a Miyota 9015, a Seiko NH35A, or a decorated Chinese automatic. Genuine caliber 35111 shows striped bridges and a skeleton rotor.

Beat rate test

A timegrapher settles the movement question. Caliber 35111 runs at 28,800 vibrations per hour. The Miyota 9015 also runs at 28,800. The Seiko NH35A runs at 21,600. A reading of 21,600 on a watch sold as genuine points to a movement swap. A reading of 28,800 does not prove the watch is real, because two common replica movements share that rate.

Weight and finish

Weigh the watch. A genuine Mark XVIII on a leather strap sits near 70 g. Replicas land within 10 g either side, so weight alone does not settle the question. Look at the lug edges and the bezel polish. Genuine parts break with a machined line. Replica edges roll over and lose the line under a loupe.

Price signals

Used genuine Mark XVIII examples trade between about $3,000 and $5,000 on the secondhand market. Replica listings run $200 to $600 based on movement and case finish. A genuine watch offered at $800 is not genuine. Ask for the box, the warranty card, and the service record.

Verification steps

  1. Read the caseback reference and serial. Compare the digits to the paperwork.
  2. Measure the case with calipers. Genuine measures 40.0 mm, crown excluded.
  3. Run a timegrapher and read the beat rate.
  4. Take the watch to an IWC boutique or service center. IWC does not offer a public online serial lookup for owners.

Repair records, service papers, and a seller who allows an inspection carry more weight than any single photo.