Short Answer
A fake IW323746 gives itself away in a set order: case finishing first, dial printing second, movement and caseback engravings third, paperwork last. Replicas at the top of the market copy the silhouette well and the small details poorly, so a 10x loupe and one look through the display back settle most questions in a few minutes. If the seller will not let you open the case or take the watch to a watchmaker, treat the offer as counterfeit.
What the Reference Should Be
The IW323746 sits in IWC's 3237 reference block, a group of stainless steel automatic models that share a case architecture and a display back. Case diameter, dial variant, calibre and bracelet options change by production year. Pull the official specification for the exact variant in front of you before comparing anything, because "wrong" only means something against a baseline. IWC publishes reference numbers, case materials and calibre data, and an authorized service center can check a serial number against the factory record.
Prerequisites
- A 10x jeweler's loupe
- A bright, diffused light source
- Calipers or a ruler with millimeter marks
- A digital scale that reads to 0.1 g
- A phone camera with macro capability
- The seller's asking price and full provenance in writing
Step-by-Step Authentication
- Measure the case diameter, thickness and lug width with calipers.
- Weigh the watch head on the scale and compare it with the documented weight for the reference.
- Examine the case flanks, lug tops and crown guards under 10x magnification.
- Compare the bezel, crystal and case proportions against official photographs of the same variant.
- Read every line of dial printing with the loupe.
- Check the applied indices and hands for height, alignment and lume fill.
- Wind the crown and set the time and date to judge the action.
- Turn the watch over and study the caseback engraving.
- Compare the reference number and serial number against the paperwork.
- Inspect the movement through the display back with the loupe.
- Work the bracelet, clasp and end links by hand.
- Verify the box, warranty card and service records.
- Compare the asking price with recent sold prices for the same reference.
- Have a qualified watchmaker open the case and confirm the calibre.
Case Finishing
Genuine IWC case work keeps a uniform grain direction, crisp polished chamfers and a sharp break between brushed and polished surfaces. Replicas show rounded chamfers, uneven brushing on the lugs, and polishing that bleeds across the line where the two finishes meet. Look at the transition at the lug root and under the bezel, since that is where shortcuts show. Run a fingertip along the caseback edge and the crown teeth: stamped parts leave a soft, rounded edge, machined parts leave a defined one.
Dial Printing and Applied Markers
Print sits level, sharp and even in weight on a genuine dial. A loupe reveals dot-matrix edges, double-struck letters or paint that floats above the surface on a fake. Applied indices sit flat and parallel to the dial with clean feet. Check alignment at 12 and at 6, where a 0.2 mm drift is easy to see. Lume fill should reach the index walls without overflow, and index color should match the hands.
Caseback Engraving and Serial Numbers
Reference and serial numbers on genuine watches are cut into the metal with consistent depth and spacing. On replicas the depth varies, the font drifts, and the same serial often appears across several listings, which is the fastest way to confirm a fake. Ask two sellers for photos of the same reference and compare the digits. The numbers must match the warranty card and the movement. A serial that an authorized service center cannot trace, or a card with mismatched digits, ends the conversation.
Movement
Through a display back you can judge rotor engraving, bridge finishing, jewel settings and balance construction. Genuine IWC automatics in this block carry a branded rotor with correct engraving depth and a serial consistent with the case. Fakes use stock Asian automatics or decorated copies with shallow engraving and mismatched fonts. Put the watch on a timegrapher: a beat rate that does not match the documented frequency for the calibre is disqualifying.
Bracelet and Clasp
Check link fit, side play and the fastener type. Genuine bracelets use screws or fitted pins with correct thread depth, and the clasp carries deep, even stamping with a firm folding action. Replicas use push pins where the original uses screws, and stamped clasps with light engraving and a loose snap.
Box, Papers and Price
Warranty cards have cardstock weight, print quality and font spacing that fakes rarely match. Then compare money. A stainless steel IWC automatic offered at a small fraction of recent sold prices is counterfeit, and a price that sits oddly low against three comparable sales is the same warning with a different label.
Replica Tiers You Will See
- Budget builds: quartz or basic automatic movement, wrong case size, painted indices.
- Mid builds: correct dimensions, printed dial, stock automatic, shallow engraving.
- High builds: close dimensions, copied dial, decorated movement, near-correct weight, and failure on engraving depth, movement serial and paperwork.
When to Walk Away
- The seller refuses an inspection or a watchmaker's opening.
- The serial number appears in more than one listing.
- Papers and box are "lost" while the watch is sold as new.
- Photos are stock images or show a different variant each time.
- Payment is requested by wire or crypto with no return option.
Authentication is a comparison exercise, not a gut check. Get the official specification, get magnification, get the case open, and let the details decide.