Short answer
IW323730 uses the IWC reference format: an IW prefix plus six digits. I could not verify this number in the IWC catalog pages that dealers cite. Confirm the reference with an IWC boutique or service center before you send money. If the number cannot be confirmed, the watch has parts value and nothing more.
Step 1: Confirm the reference
IWC sorts references into blocks by family: Pilot's Watch, Portugieser, Ingenieur, Aquatimer, Portofino, Da Vinci. Ask the seller for a photo of the caseback. Compare the number on the case with the number on the warranty card and the box label. All three must match. A mismatch means the watch is a build, not an IWC.
Step 2: Read the caseback
- Engraving depth. Real IWC backs are stamped or laser marked with sharp edges. Replica backs show shallow, rounded letters.
- Text. "International Watch Co." and "Schaffhausen" use a set font. Spelling errors and odd spacing show up on fakes.
- Serial. IWC serials appear on the caseback and on the movement. Ask for both photos in one shot.
- Material marks. Steel, titanium, and gold cases carry different stamps. A gold stamp on a steel case is a red flag.
Step 3: Check the movement
IWC movements in this number range are in-house. Replica sellers fill cases with ETA 2824 copies, Asia 7750 chronograph movements, Seagull ST19, or Miyota 9015. Four points to inspect:
- Rotor. Real rotors carry the IWC medallion or engraved "Probus Scafusia" text. Copies use printed decals.
- Screws. Blued steel screws show a dark blue tone that shifts under light. Painted screws look flat.
- Spacers. A movement that is too small for the case needs a ring. Real IWC movements fill the case.
- Timegrapher. Ask for a printout. A rate outside plus or minus 10 seconds a day and a beat error above 0.8 ms point to a low grade caliber.
Step 4: Measure the case and dial
Ask for a caliper photo of case diameter, thickness, and lug width. Compare the numbers to the IWC spec sheet. Replica cases run 0.5 mm to 1 mm off. Check the crystal: IWC uses sapphire with anti-reflective coating on two sides. The coating shows a faint blue tint. A strong purple or green tint points to coated mineral glass. Under a 10x loupe, applied indices on a real dial have polished bevels and level lume plots.
Step 5: Price and paperwork
A new IWC in steel sells from about $5,000 to $10,000. Used models start near $3,000. Listings at $300 to $900 for a "1:1 Swiss super clone" are counterfeits. Boxes and warranty cards are sold as loose items, so paperwork alone proves nothing.
Legal and shipping risk
Importing counterfeit watches into the US is illegal under 19 U.S.C. 1526. Customs seizes the shipment and can issue a penalty. Wire and crypto payments leave no chargeback path. The buyer carries the loss.
Verification checklist
- Get the caseback photo, the movement photo, and a timegrapher printout.
- Ask for a caliper shot of diameter, thickness, and lug width.
- Check the reference and serial with an IWC boutique or service center.
- Have a watchmaker open the case before you pay.
- If the seller refuses any step, walk away.