Quick answer

IW323791 is an IWC Aquatimer reference. Replicas of Aquatimer models are common, and most fail on four points: caseback engraving, movement, bezel action, and dial print. Check those four first. A serial lookup through an IWC service center is the step that settles the question.

IWC does not list every past reference on its current site. Confirm the case size, caliber, and production years with an IWC service center or an archived catalog before you compare a watch to anything.

Case and caseback

  • Genuine caseback engraving has even depth, sharp edges, and one consistent font. Replica engraving looks shallow, with rounded letters and uneven spacing.
  • The reference number and serial number sit in fixed positions. Ask for a straight-on photo of the caseback, not an angled one.
  • Real cases carry satin brushing on the sides and polished edges. Replicas show buffing marks and soft transitions.
  • Measure the case. Many replicas run 0.5 mm to 1 mm off the listed diameter.

Dial and hands

  • Print quality is the fastest tell. Genuine dial text has crisp edges. Replica text has thicker strokes and uneven kerning.
  • Lume plots on the real dial sit in recessed cutouts. Replica plots sit on the surface or sit low in oversized cutouts.
  • The date aligns with the aperture. Replicas show the date off center, or a date font that differs from the rest of the dial.
  • Original hands have polished chamfers. Replica hands look flat under a loupe.

Bezel and crown

Several Aquatimer references use an internal rotating bezel driven by an outer ring or a second crown. Turn the control and count the clicks. Replica bezels feel loose or grind. Genuine bezels index with firm detents and no play. Screw the crown down. It should seat with light pressure and stop clean. A crown that binds, or threads past the case, points to a replica.

Movement

Ask for a photo of the movement if the reference has a display back. IWC uses in-house calibers and modified ETA base calibers, depending on the year. Replicas ship with Asian clones, and rotor engraving does not match IWC markings. A watchmaker can name the base movement in minutes. If the seller refuses a movement photo or an inspection, stop there.

Listing red flags

  • Price below 40 percent of the market range for the reference.
  • Photos borrowed from another listing. Run a reverse image search.
  • No serial number in the photos, or a blurred serial.
  • Seller refuses a video call, escrow, or a return window.
  • Papers with a font that does not match IWC documents for that year.

Verification steps

  1. Get the full serial number and reference from the caseback.
  2. Send both to an IWC service center or an authorized dealer for a lookup.
  3. Pay a watchmaker for a movement inspection and a water resistance test.
  4. Buy through a platform with an authentication program, or use escrow.

Water resistance matters more on a dive watch than on any other type. A replica sold as a 2000 m dive watch will not hold that pressure. Skip the pool test and let a watchmaker pressure test the case.