Short answer
A fake IW329022 gives itself away on three points: case dimensions, dial printing, and the movement. Measure the case with calipers, read the caseback engraving under a loupe, then compare both against the spec IWC publishes for that reference. If the numbers do not line up, stop there. No amount of box, papers, or seller talk fixes a case that is half a millimeter off.
Prerequisites
- Digital calipers accurate to 0.01 mm
- 10x jeweler's loupe
- Bright, diffused light and a plain background
- A camera for close-up photos of the dial, caseback, and movement
- The published IWC spec sheet for the reference you are checking
- A watchmaker who will open the case if the seller allows it
Steps
- Measure the case diameter, thickness, and lug width with calipers, and write the numbers down before you look at anything else.
- Weigh the watch head on a kitchen scale, since clones are often lighter or heavier than the steel case the reference calls for.
- Read the caseback engraving under the loupe and check that the reference number, serial, and material stamp are crisp, straight, and evenly spaced.
- Confirm that the reference on the caseback matches the dial configuration, because a mismatched dial and caseback is the most common error on copies.
- Study the dial text at 10x, focusing on letterforms, the gap between the I and the W, and the thickness of the printing.
- Check the applied markers, which should sit flush to the dial with evenly filled lume and no visible adhesive.
- Compare the hand length to the minute track, then look at the finish on the hands for burrs, rough edges, or a dull sweep second hand.
- Set the watch to 11:58 and watch the date change, noting whether it snaps cleanly or drags across the window.
- Wind the crown and feel the threads, which should engage smoothly within the first half turn and seat without grit.
- Open the caseback with the correct tool and inspect the movement for rotor engraving, jewel count, and surface finishing.
- Photograph the movement and compare the stamping to the caliber IWC lists for this reference, including the shape of the balance bridge.
- Book a check with an independent watchmaker or an IWC service center, and treat that verdict as final.
Tells that show up most often
- Case thickness off by half a millimeter or more
- Fuzzy or doubled printing on the dial
- Lume that sits proud of the marker instead of level with it
- A date wheel that is not centered in the window
- Rotor engraving with the wrong font or wrong jewel count
- Strap stitching that is heavier and more uniform than the original
- Caseback screws that are a different size or thread pitch
Why measurements beat opinions
Photos on a listing page hide small errors, and sellers know it. Calipers do not. A case that measures wrong will not fit genuine straps, genuine service parts, or a genuine bracelet, and a watchmaker will spot the mismatch in seconds. Dial printing is harder to judge from a screen, so magnify it and compare letterform by letterform against a known-good example. Movement checks carry the most weight, because most copies use a stock or lightly decorated caliber that does not match the architecture of the original. Ask for a movement photo before you commit, and refuse any deal where the seller will not allow an inspection. Boxes and papers are easy to reproduce and should never be treated as proof of anything.
Where to verify
Use the manufacturer's own reference data for dimensions and caliber, a national customs or trade body for counterfeiting trends in your market, and a qualified watchmaker for the physical inspection. Those three sources settle nearly every question a listing leaves open.