Short answer
A fake IW323793 almost always gives itself away in three places: the caseback engraving, the date window, and the movement visible through the back. Genuine IWC engraving is cut deep, sits crisp under a loupe, and keeps even spacing across the whole line of text. Replica stamping is shallow, slightly rounded at the edges, and often drifts off center. If the seller also wants cash only, has no service history, and the price sits at a fifth of market, you have your answer already.
What the reference number actually means
IWC builds its references as IW plus six digits. The first four digits identify the model and the case, while the last two point to a specific variant, meaning dial color, case finish, or bracelet versus strap. So IW323793 is one configuration inside the 3237 family, not a model name on its own. A seller who cannot say which variant they are holding, or who lists one number above a photo of a watch with the wrong dial, is not someone to buy from.
The checks that matter
Caseback and engraving
Run a fingernail across the reference number. On a real IWC you feel a sharp, defined groove. On most fakes it feels like a scratch or a print. Look at the spacing between characters, then compare the font weight to photos on the brand's own archive. Replicas usually get the letter shapes close and the proportions wrong.
Dial, hands, and date
Check the printing under magnification. Applied markers on a genuine watch sit flat and catch light evenly. On a replica, one marker is often set a fraction too high or tilted. The date wheel is the other giveaway: look for off-center numbers, a font that differs from the dial text, or a window that is not perfectly rectangular at the corners. Lume plots should match the hands in color and application depth.
Movement and finish
Where the case has a display back, the movement finish tells you more than any dial detail. Look for Geneva stripes with consistent depth, blued screws that are actually blued rather than painted, and a rotor engraving that matches the reference. Replica movements often skip the perlage, and the rotor text is laser-etched too lightly.
Crown, bezel, and bracelet
Screw the crown in and out. Genuine threads engage smoothly and stop with a soft, definite seat. Replica threads feel gritty or catch partway. Turn the bezel or pushers: they should move with even resistance, no wobble, no slack in the detents. On the bracelet, check the clasp stamping and the end-link fit. Genuine links sit flush with no visible gap against the case.
Weight and feel
Replicas are usually lighter than the real thing, though not always by much. Hold it in one hand and compare against the published weight for that configuration if you can find it. A watch that feels top-heavy or hollow in the case is worth a second look.
Papers, boxes, and price
A box and card prove nothing on their own. Packaging is copied well and sold separately. What matters is whether the serial on the case matches the paperwork, whether the seller can name the dealer, and whether the price makes sense. If the number is several thousand below every comparable listing, the watch is either stolen, broken, or fake.
Before you hand over money
- Ask for macro photos of the caseback, date window, and clasp.
- Request a video of the crown threading and the seconds hand sweep.
- Meet at a watchmaker who can open the case, or use an escrow service.
- Walk away from any seller who resists an inspection.
None of these steps takes more than a few minutes. They save you from the one purchase you cannot undo.