A reference number does not authenticate a watch. IW329087 sits in a real IWC numbering block, and counterfeiters copy real numbers precisely because buyers search for them. So the short answer: if a seller treats "IW329087" as proof of anything, that alone is a warning. You check the watch first, then match it to the number.

What the number actually points to

The 3290 block is IWC's Pilot's Watch Automatic family, a compact three-hand pilot watch with a date, roughly 36mm across depending on the variant. Clean dial, no chronograph, one crown. Because the design is simple, it is also one of the easiest shapes in the line to copy, which is why so many listings carry a 3290-style reference.

Before anything else, pull the exact variant up on IWC's own reference page. Dial colour, case metal, strap or bracelet, and whether it was a limited run all vary inside the same block. If the watch in the photos does not match the spec that reference is supposed to have, stop there.

Why this model gets faked so heavily

Three reasons. It is popular. It has a solid caseback on many versions, so you never see the movement. And a plain three-hand dial hides sloppy work better than an openworked or chronograph layout would. Fakers pick targets where the buyer cannot inspect much.

The checks that hold up

Case and proportions

Measure it. A 3290-series Pilot's Automatic is a small watch. If the listing measures closer to 40mm, the number does not belong to that case. Look at the lugs too. Genuine IWC lugs have a crisp, even bevel and the brushing runs one direction without swirl marks.

Dial and printing

Under a loupe, IWC text is sharp and evenly spaced with no bleed at the edges. The applied markers should have polished sides and flat, uniform tops. On replicas the markers often sit slightly crooked or the lume pad is a different shade from the hands.

Date window

This is where most fakes fall apart. Check the font of the numerals, the thickness of the date wheel, and whether the number sits centered in the aperture. A date that hugs one edge, or a wheel that looks paper-thin, is a tell.

Crystal and coating

IWC pilot watches typically carry anti-reflective treatment that makes the glass nearly disappear at an angle, with a faint tint under certain light. Cheap crystals reflect like a mirror. That difference is obvious side by side and hard to fake at low cost.

Caseback and engravings

Engraving depth matters. Genuine laser or stamp work is deep, clean and consistent. Look at the reference and serial fonts, the spacing between characters, and whether the reference stamped on the back is even correct for the case in front of you. Mismatched numbers happen more often than you would think.

Movement and winding

Many current IWC three-hand automatics beat at 28,800 vph. A timegrapher will show you the rate and beat error in seconds, which settles the question faster than any photo. Wind it by hand and feel for grit. A rotor that rattles like a tin can is not a good sign.

Papers, price and the seller

A price far below market on a watch that is supposedly genuine is the oldest signal there is. Warranty card, box, and a serial that IWC can confirm through a boutique or service center all matter. Buy the seller as much as the watch.

What a good replica still gets right

Honesty here: modern high-grade replicas of simple pilot watches pass a casual glance. Case dimensions, dial layout and even the beat rate can be close. What they rarely match is the finish on the movement, the AR coating quality, and the engraving depth. If you are knowingly buying replica grade, the standard should be that it is sold to you as a replica, never passed off as genuine.

Ask a seller these questions

• What is the exact reference on the caseback, and does it match the dial variant?
• Can you photograph the caseback engraving straight on, in daylight, without glare?
• What is the measured case diameter, lug to lug, and thickness?
• Does it come with the original warranty card, and can the serial be confirmed?
• Will you accept a return if a watchmaker finds the movement is not IWC?

Bottom line

IW329087 is a number, not a guarantee. Verify the reference against IWC's own listing, measure the case, inspect the date and dial print, and put it on a timegrapher if you can. When a seller resists any of that, you already have your answer.