For an IW328071 the most reliable check is an IWC service center inspection with the serial number matched against the brand's own records. The criteria that decide the outcome are the reference and serial, case and finishing, dial printing, movement and caseback engraving, and the paperwork behind the asking price. A reference number is a search term, not a certificate, so treat a listing that leads with fake IW328071 or replica IW328071 as a statement about which watch the seller wants you to see rather than proof of what is in the box.
Reference number and serial number
The IW prefix is IWC's own reference code, stamped on the caseback and repeated on the warranty card. It is also the easiest element on a watch to copy, which is why the serial matters more than the reference.
- Consistent with genuine: reference and serial cut in the factory font, with no polishing haze around the engraving, and a card showing the same serial.
- Consistent with genuine: a seller willing to send the serial to a dealer or service center for a check before payment.
- Consistent with a replica: the same serial appearing in two separate listings, or a card with a number that does not match the case.
- Consistent with a replica: shallow laser engraving, rounded letter edges, or uneven spacing between characters.
This section matters most for private secondhand sales, where there is no dealer warranty behind the watch.
Case, bezel and finishing
- Consistent with genuine: lugs with a defined edge, brushing that runs in one direction, and a crisp line where brushed and polished surfaces meet.
- Consistent with genuine: a crown that threads smoothly and sits level, and a case thickness that matches the published specification for the reference.
- Consistent with a replica: softened lug edges from casting rather than machining, brushing that runs the wrong way, or polished flanks that bleed into brushed ones.
- Consistent with a replica: a gritty crown, a case a fraction of a millimeter thick or thin, and spring bars with visible play.
Case work is the hardest thing for a copy to get right and the easiest thing to photograph badly, so ask for angled shots in daylight.
Dial, hands and lume
- Consistent with genuine: applied markers set level and flush, text that stays sharp under a 10x loupe, and a date aperture with a clean inner edge.
- Consistent with genuine: lume that charges and fades at the same rate across every marker and the hands.
- Consistent with a replica: fuzzy or doubled printing, uneven spacing between lines of text, markers that sit tilted or stand too tall, and a date font that does not match the reference.
- Consistent with a replica: lume that glows a different shade from the hands or dims within minutes.
Movement and caseback
- Consistent with genuine: a movement that matches the beat rate, power reserve and functions published for the reference, with a signed rotor and finishing that holds up under magnification.
- Consistent with genuine: caseback text cut deep and even, with the same font weight across all lines.
- Consistent with a replica: a decorated generic movement, a blank or wrongly engraved rotor, or a seconds hand that sweeps at the wrong frequency.
- Consistent with a replica: flat caseback text, screw heads of the wrong type, or a display back showing a movement family the reference never used.
Box, papers and service history
- Consistent with genuine: a warranty card, booklet and box that match the reference, a dealer stamp, and service receipts that name the serial.
- Consistent with genuine: a documented ownership trail that lines up with the production period of the reference.
- Raises doubt: papers described as lost, a generic box, or a card printed with a different reference.
- Raises doubt: a full set offered at a price far below the rest of the market for the same reference.
Price, seller and the law
- Consistent with genuine: pricing in line with the current secondhand market, a written return window, and a seller who welcomes a third party inspection.
- Consistent with a replica: a price far under market, reused listing photos, payment methods with no dispute process, and a refusal to allow authentication.
In the United States, importing or selling counterfeit goods is illegal, and a high grade copy is still a counterfeit. Brand service centers generally decline to service them, and genuine parts will not fit.
Verification order that saves time
- Ask for the reference and serial in writing, plus clear photos of the caseback and the card.
- Compare every visible detail against IWC's published specification for the reference.
- Inspect the dial and engraving under magnification instead of on a phone screen.
- Send the watch to a service center or an independent watchmaker for a movement inspection.
- Pay only after the inspection, through a method that offers a dispute process.
Which route fits which buyer
If you want certainty, buy from an authorized dealer or from a dealer who puts authentication in writing, and let the price reflect that protection. If you buy private, budget for an inspection and treat it as part of the cost of the watch. If you already own a replica, plan on independent service only, because the factory will not take it in.