Short answer: "IW9380601" does not match IWC's published reference format, which uses IW followed by six digits. Treat the string as a seller SKU, a listing code, or an engraving on a replica caseback, not as a factory reference you can look up. That single fact changes the comparison: you are not checking a replica against a known catalog entry, you are checking a watch against the general standards IWC applies to every piece it ships. Do the checks below before any money changes hands.
What the Code Tells You
A genuine IWC carries a reference number and a separate serial number, both engraved in consistent depth and typeface. When a listing leads with a long numeric string that no dealer can match to a catalog entry, the paperwork usually does not exist either. Ask the seller for the reference number, the serial, and a photo of the caseback engraving in the same frame. If any of the three is missing, stop there.
Prerequisites
- A 10x jeweler's loupe
- Digital calipers readable to 0.1 mm
- A kitchen scale accurate to 1 gram
- Photos of the genuine model from the brand's own catalog, at several angles
Step-by-Step Comparison
- Measure the case diameter and thickness with the calipers and compare both numbers to the published specification. Replicas routinely run 0.3 to 1.0 mm thick because the movement and caseback geometry differ.
- Weigh the watch head on the scale. A genuine piece in steel or gold lands within a few grams of the catalog figure; a plated brass or thin-walled case falls short.
- Set the watch under the loupe and read the dial text. Genuine printing sits sharp at the letter edges with even spacing; replica printing shows bleed, uneven stroke weight, or a font that is subtly wider.
- Inspect the hands at the same magnification. Look for a burr on the edges, uneven lume fill, and a seconds hand that does not sit flat above the minute track.
- Check the date window alignment if the model has one. The numeral should be centered with equal gaps on all four sides at every date position.
- Turn the watch over and examine the caseback engraving depth and the crispness of the reference and serial digits. Laser etching on replicas often looks shallow and slightly hazy under raking light.
- Open the caseback only with the seller's permission, then compare the movement finish, rotor engraving, and jewel count to factory photos. A decorated rotor over an undecorated bridge is a common replica shortcut.
- Work the crown through all positions and set the time. Genuine winding is smooth with defined clicks; a gritty or loose feel points to a substitute movement.
- Flex the bracelet and check end-link fit against the lugs. Any daylight gap or lateral play is a fitment problem the factory does not ship.
- Cross-check the serial against the warranty card, the box label, and the caseback. All three should match character for character.
Where Replicas Consistently Fall Short
Replica cases are usually machined from a different alloy than the original, so the color temperature of the metal reads slightly warm or slightly gray next to a genuine piece. Movement finishing is the second gap: plates and bridges on replica movements are often plated rather than properly finished, and the engraving is stamped or lasered instead of applied with the depth a factory uses. Dial furniture is the third. Applied indices on replicas tend to sit a fraction high, and the lume compound is flatter and less densely packed than the factory application.
Price and Paperwork Reality
A price far below the current secondary market for the model is the strongest single signal. Genuine watches depreciate in a predictable band; a discount of 60 percent or more against dealer asking prices does not happen on an authentic piece. Photocopied cards, blank warranty booklets, and boxes with mismatched labels all point the same direction.
Legal Note
Selling a counterfeit watch as genuine is trademark infringement in the US and the goods are subject to seizure at import. Buying one knowingly carries risk that is hard to reverse at resale, since no reputable dealer will authenticate or take it in trade.