For a suspect IW329032, the single most reliable check is a movement and serial verification performed by an IWC authorized watchmaker, because it compares the watch in your hand with the manufacturer's own records instead of a photograph. The three criteria that settle the question are reference-level documentation, movement and serial consistency, and external finishing that matches the production period. A good counterfeit passes a screen test. It fails a records test.

1. Start with the manufacturer's reference data

Before you judge any example, establish what IW329032 is supposed to be: case material and diameter, dial variant, movement family, and the years it was sold. Counterfeits are built to a photograph, not a spec sheet. If the case size is wrong for that reference, or the dial text is laid out the way another reference lays it out, you can stop there. Ask for a sharp, straight-on photo of the caseback and read the engraved reference number character by character, including the spacing and font weight.

Pros

• Free, fast, and usable from a listing photo before any money moves.
• Filters out most careless fakes in minutes.

Cons

• Depends on the seller providing clear, well lit images.
• Confirms the model, not the individual watch. A correct reference number can still sit on a counterfeit case.

Best for: the first five minutes of an online deal, and for screening several listings quickly.

2. Movement and serial engraving

A genuine IWC movement carries finishing, engraving and a serial that an authorized watchmaker can match to the case number. Counterfeit movements are often decorated to look convincing from one angle but show mismatched screw heads, uneven perlage, or rotor engraving with the wrong depth or font. The caseback serial and the movement serial should belong together, and both should appear in the manufacturer's records for the reference. A watchmaker can also confirm beat rate and power reserve against the specification for that calibre.

Pros

• Effectively conclusive when the records match.
• Catches high-end fakes that copy the exterior well.

Cons

• Requires opening the case, which you cannot do to a watch you have not bought.
• Usually means a service appointment and sometimes a fee.

Best for: any purchase where the amount at stake justifies a professional inspection.

3. Case, crown and finishing

Check the brushing direction on the lugs, the sharpness of the case flanks, and the transition between polished and brushed surfaces. Genuine cases feel crisp along the edges. Counterfeits often feel soft or slightly rounded because the case was polished after machining. The crown should turn smoothly and the threads should engage without grinding. Look at the crystal under a lamp: the dial should stay readable from an angle, and any anti-reflective treatment should look even rather than patchy.

Pros

• No tools needed, and it works in the hand.
• Finishing is expensive to copy, so this is where many fakes show themselves.

Cons

• Subjective, and hard to judge from compressed photos.
• Wear and previous polishing can make a genuine case look wrong.

Best for: in-person viewings and second-hand watches with no service history.

4. Dial print, hands, date and lume

Under a loupe, genuine dial printing has clean edges and consistent letter spacing. Look for ink bleed, thickened strokes, or brand text set too close to the rim. The hands should be the right length for the markers, with clean bevels and no file marks. Lume should sit level inside each marker rather than spilling over the edge. The date window is a frequent failure point: check the font, the position of the numerals inside the aperture, and the colour of the date disc against what the reference should have.

Pros

• Small details are cheap to approximate and expensive to get exactly right.
• A 10x loupe costs little and reveals a lot.

Cons

• Some genuine dials vary slightly between production batches.
• Refinished or replaced dials confuse the comparison.

Best for: close-range checks once a seller has agreed to a meeting or has sent a detailed photo set.

5. Strap, buckle, box and papers

Boxes, booklets and warranty cards are widely copied and prove almost nothing on their own. What matters is whether the numbers agree. The reference and serial on the card should match the caseback, and if there is a service record, the serial on it should match too. On the strap or bracelet, check the engraving on the buckle or clasp for depth and font, and look at stitching tension and edge finishing on leather.

Pros

• Matching documentation and serials raise confidence and resale value.
• Easy to verify from photographs.

Cons

• Paperwork is the easiest part of a package to fake.
• Genuine watches are often sold without full sets, so absence alone proves nothing.

Best for: pricing decisions and for judging how well a watch has been kept.

6. When to walk away

If a watch is offered far below the going rate for that reference, treat it as counterfeit until an authorized watchmaker says otherwise. Ask for the caseback serial before you travel, decline any deal that depends on a rushed decision, and remember that a first copy, however close it looks on a photo, has no manufacturer service behind it and no parts supply if the movement fails. On a watch of this class, the inspection is the cheapest part of the purchase.