Short answer

I cannot confirm that IWC catalogued a watch with the reference IW329078. Published IWC product lists in the IW329xxx block cover Aquatimer models, and no IW329078 page appears in those lists or in public watch databases. Two readings follow. Either the seller moved digits, or the number was invented. A watch sold as IW329078 needs document proof before money changes hands.

What a real IWC reference looks like

IWC formats references as IW plus five digits, for example IW329001. The digits are stamped on the case back, printed on the warranty card, and listed on the IWC service record. All three must match. A case back with laser-printed digits, uneven spacing, or a font that differs from the warranty card points to a swapped case back. Swapped case backs are common on replica cases.

Checks in order

  1. Reference and serial. Ask for a photo of the case back at an angle. Genuine engraving sits below the surface of the metal. Acid-etched or printed digits sit on top.
  2. Movement. Recent 42 mm Aquatimer Automatics run IWC calibre 30120 on a Sellita base. A replica will hide a Chinese automatic or a quartz movement behind a display back. Rotor text and jewel count matter.
  3. Dial text. Check letter spacing in the Schaffhausen line and the position of the date window. Repainted dials show dust under the lacquer and crooked indices.
  4. Case dimensions. Weight and thickness are the first things replica makers lose. A 42 mm Aquatimer Automatic comes in near 120 g on the steel bracelet. Ask for a photo on a scale.
  5. Papers. Warranty cards carry reference, serial, and dealer stamp. Blank cards and mismatched serials are the most frequent fault.
  6. Service history. IWC service centers in Schaffhausen and the United States log every watch they handle. A private seller can be checked with the serial.

Prices

Used Aquatimer Automatics sell in the low thousands of US dollars. Asking prices on the secondary market cluster between $3,000 and $5,000, set by condition, bracelet, and box. A listing far under that band is the strongest signal on its own. Replica Aquatimers sell for $100 to $400. A full IWC service costs several hundred dollars and can take months.

Where to verify

IWC publishes its current catalog and a reference lookup. Watch databases log discontinued references with photos. Auction archives show past sale results with case details. A dealer who refuses a serial check, or who supplies catalog photos as listing photos, ends the conversation.