Short answer

A fake IW329065 shows itself in three places first: the case back engraving, the dial printing, and the movement behind the display back. Counterfeiters copy the outline well. They seldom match the fonts, the finishing, and the tolerances. Work through those three areas before you look at anything else, then confirm the small details.

What you need before you start

  • A 10x loupe or a phone macro lens, plus a bright diffused light.
  • Official catalog photos of the reference, saved offline for side by side comparison.
  • A jeweler's scale that reads to 0.1 g, and calipers if you can borrow them.
  • The seller's written agreement on a return window and on inspection.

1. Confirm the reference and case numbers

Genuine IWC case backs carry the reference number and a separate case number. Both are cut into the metal with clean edges and even depth.

  1. Read the reference number and confirm it matches the model being sold.
  2. Record the case number and ask whether it appears on the warranty card and the service papers.
  3. Compare the letterforms with official photos. Many fakes use a wider, rounder font.
  4. Check that the numbers sit inside a clean recess with no tool chatter around them.

2. Inspect the engraving and case finish

  1. Run a fingernail across the engraving. Real cuts have sharp walls and flat floors. Shallow, saucer shaped grooves point to a fake.
  2. Check the brushed and polished transitions on the lugs. A fake leaves a soft, wandering line where the two finishes meet.
  3. Look at the case flanks under raking light for polish marks a factory would not ship.
  4. Thread the case back on and off, if the seller allows it, and feel for grit or wobble.

3. Compare the dial, hands, and date

  1. Match every printed element to the catalog photo, including the brand mark, the model line, and any depth rating.
  2. Study the print under magnification. Genuine print has hard edges. Fakes show fuzzy or doubled edges.
  3. Check the hands for correct length, level mounting, and lume that fills the frame with no gaps or overflow.
  4. Charge the lume with a phone light for 20 seconds, then compare brightness and color with known photos.
  5. Study the date aperture if the reference has one. The window should be sharp and the disc font should match the dial.

4. Study the movement

If the reference has a display back, the movement is your strongest evidence. Photograph it through the sapphire and compare it with service photos of the same caliber.

  1. Match the caliber number on the movement to the caliber listed for the reference.
  2. Check that the rotor text is centered, straight, and cut with even strokes.
  3. Look for perlage or Geneva stripes that run off a bridge edge or fade in one corner.
  4. Wind the watch and set the time. The crown should feel smooth, with clear detents and no grinding.
  5. Lay the watch flat and check the rate over 24 hours. A genuine movement holds a tight spread.

5. Weigh it and measure it

  1. Weigh the head alone, then the complete watch with its bracelet or strap.
  2. Compare the totals with the published figures. A gap of more than a few grams points to a different alloy or a hollow case.
  3. Measure diameter, thickness, and lug width with calipers and check them against the spec sheet.

6. Check the crown, bracelet, and clasp

  1. Confirm the crown logo is crisp and correctly oriented.
  2. Check that end links seat against the case with no gaps.
  3. Open and close the clasp several times. It should snap without play.
  4. Look for stamped, hollow links where the reference calls for solid ones.

7. Go through the box and papers

  1. Compare the warranty card number with the case number.
  2. Check the printing quality on the card and booklet.
  3. Ask for service receipts and call the service center to confirm the case number was handled.

Red flags that settle it

  • A seller who refuses close up photos of the case back.
  • A price far below the going rate for the reference.
  • Numbers that do not match between the case, the card, and the box.
  • A refusal to meet at a boutique or an independent watchmaker.

If you are still unsure

Take the watch to an IWC boutique or a watchmaker who services the brand. Pay for a written assessment before money changes hands. The fee is small next to the cost of a counterfeit.