The short answer
A fake IW329148 is a replica of an IWC pilot's watch, and like most replicas it copies the shape first and the details last. At arm's length it reads as the real thing. Under a loupe or on a caliper it gives itself away, most often at the date window, the caseback engraving, and the movement inside.
So the useful question is not "is this fake" but "which tier of fake is it, and does the price match that tier." A $300 replica that nails the dial is fine value. The same watch sold to you as genuine at $3,000 is a problem.
Start with the real spec, not the photos
Pull the reference from IWC's own site or an authorized dealer before you compare anything: case diameter, thickness, lug width, calibre number, power reserve, crystal treatment, water resistance. Replicas get built against product photos, so they drift on the numbers nobody photographs. Thickness is the one that goes wrong most. If you can, put calipers across the case and compare.
Where replicas fall apart
Dial and date
Print quality, index polish, and above all the date wheel. A genuine IWC date font is thin, sharp and centered in the window. Fakes sit high or low in the aperture, and the numerals carry extra weight.
Lume
Super-LumiNova on the genuine article glows even and fades slowly. Cheap replicas glow patchy, or die within a minute of leaving the lamp.
Crystal
IWC uses sapphire with anti-reflective coating on both faces, so the dial almost vanishes at an angle with only a faint tint. Fakes show a heavy blue or purple wash.
Caseback and engraving
Look at engraving depth and edge quality. The reference, the serial, "SWISS MADE", the Schaffhausen line. Laser-etched fakes look shallow and slightly fuzzy at the borders. Genuine engraving has crisp walls.
Movement
The IWC 35111 family is built on a Sellita SW300-1 base, finished and regulated in Schaffhausen. Fakes run a clone of an ETA 2824 or a Miyota, sometimes under a decorative plate screwed over the top. Check the rotor engraving under magnification, the perlage, and whether the balance wheel is a plain blank instead of an engraved one.
Price sanity check
A used genuine IW329148 trades in the thousands of dollars. A replica sells for a few hundred. If someone offers a "genuine" one at $800 with no box, no papers and a long story, the story is the product.
Checklist
- Measure thickness and lug width with calipers.
- Weigh the watch. Fakes run light, sometimes by 20 g or more.
- Inspect the date font and its alignment in the window.
- Charge the lume and watch how it fades.
- Tilt the crystal in daylight and look for the AR tint.
- Read the caseback engraving with a loupe.
- Compare the movement against photos of the real calibre.
No single test settles it. Together they sort a good replica from a bad one, and either of those from a genuine watch.