Short answer
IW329170 does not appear in IWC's reference catalog. Nothing in the current or recent lineup carries that number, so a listing built around "IW329170" is already suspect before you look at a single photo. In practice, watches sold under that string are replicas of an IWC Pilot's Watch, or a mistyped reference for a real model in the same family. Either way, you need two skills: reading IWC reference numbers correctly, and spotting the tells that separate a genuine IWC from a good fake.
How IWC reference numbers actually work
IWC reference numbers follow a fixed pattern: IW plus six digits, usually written in groups like IW3291-01 or IW329101. The leading digits map to a family, and the last digits mark the variation (dial color, strap, case metal). Sellers who invent numbers tend to break that pattern, reuse a number that belongs to a different model, or attach a real number to a watch that does not match it. When I check a listing, I pull the exact digits and compare them against IWC's own product pages, not against a reseller's description. If the number returns nothing from the brand, stop there.
First pass: case, caseback, and markings
- Reference engraving: genuine IWC cases carry the reference on the caseback, and on many models the same number appears between the lugs. The engraving cuts into the metal. Fakes often laser-print it lighter and shallower.
- Font and spacing: IWC uses tight, even lettering. Look at the spacing around "SCHAFFHAUSEN" and the serial number. Crooked baselines and uneven gaps are common on replicas.
- Caseback fit: the back should seat flush with no gap, and the screw slots on display backs should all point the same direction on a watch that left the factory untouched.
- Crown action: screw-down crowns on genuine watches thread smoothly and stop cleanly. Gritty or wobbly threading is a warning sign.
The dial does more work than the case
Applied indices on a real IWC sit proud of the dial with crisp edges and even lume fill. Fakes either print the indices flat or glue them down slightly crooked. Check the date window at 3 o'clock: the date wheel font should match IWC's own typeface, sit centered, and flip cleanly. On cheap replicas the date sits high, low, or off-center. The sapphire crystal is another tell. IWC uses anti-reflective coating on both faces, so the dial looks nearly invisible from most angles. Single-sided coating leaves a distinct blue or purple wash that you can catch by tilting the watch under a light.
Movement and the display-back test
Modern IWC Pilot's watches run in-house calibres from the 32xxx family, while earlier models used modified ETA and Sellita bases such as the 35111. In-house movements show circular graining, Geneva stripes, blued screws, and clean rotor engraving that reads "PROBUS SCAFUSIA." Replicas drop in a cheap automatic and stamp the text, so the lettering looks etched rather than engraved and the finishing is thin. If the seller refuses a clear movement photo, treat that as an answer in itself.
Buying online without getting burned
- Ask for macro photos of the dial, caseback, and crown, plus a shot with a handwritten date card next to the watch.
- Request the movement image with the rotor turned so the calibre number is visible.
- Compare every photo against IWC's official listing for that reference, item by item.
- Use escrow or a payment method with buyer protection. Counterfeit purchases generally leave you with no warranty and no recourse.
- Have a watchmaker verify the movement before the return window closes.
If you already own one
Take it to an independent watchmaker and ask for a movement identification, not a cleaning. A quick look at the balance, regulator, and rotor engraving settles the question in minutes. If it turns out to be a replica, you cannot sell it as an IWC, and you should know where you stand before you pass it along to anyone else.