Short answer: a fake IW544791 gives itself away in four places, and you can check all of them in about ten minutes. Look at the caseback engraving, the dial print and applied markers, the movement finishing, and the crown. Genuine IWC watches at this reference level are finished to a standard that replicas rarely reach once you are six inches away with a loupe.

Start With the Reference Itself

Before you compare a single detail, confirm the watch you are looking at exists in that exact configuration. Reference numbers get reused across dial colors, case metals, and strap options, and counterfeiters often combine a real reference with a dial that was never made for it. Ask the seller for a straight-on dial photo, a caseback photo, and a movement photo. If any of the three is missing or shot at an angle that hides detail, stop there.

Caseback and Engraving

This is where most fakes fall apart. Genuine engraving is shallow, crisp, and evenly spaced, cut by a laser or a stamp that leaves clean edges. On a replica the letters look soft, the depth wanders, and the reference and serial numbers sit slightly off-center.

• Check that the reference and serial fonts match across the caseback and the paperwork.
• Run a fingernail across the engraving. Real cuts catch the nail; printed or shallow-etched fakes feel flat.
• Look at the caseback fit. A genuine caseback sits flush with no visible gap and no uneven screw heads.
• Weigh it in your hand. A steel case at this size should feel dense, not hollow.

Dial, Hands, and Crystal

I look at the printing under magnification first. Genuine text has sharp terminals and consistent thickness. Replicas show fuzzy edges, uneven spacing, and markers that are glued slightly crooked.

Then the hands. Real hands have polished bevels and clean inner angles with no tool marks. On fakes you often see a flat edge where a bevel should be, or a brushed finish where the original is mirror polished.

The crystal is the tell people miss. Genuine anti-reflective coating gives a faint blue tint at an angle. A purple or green cast, or no cast at all, is a warning sign.

The Movement

A genuine watch at this reference level carries an in-house calibre with proper finishing: Geneva stripes, heat-blued screws, and clean perlage on the plates. Replicas hide a stock or cloned movement under decorative plates.

• Blued screws should be heat-treated, not painted. Painted screws look flat and slightly purple in direct light.
• Engraving on the balance cock should be sharp and legible under a loupe.
• Wind the watch slowly. Genuine winding feels smooth and progressive, with no grit and no sudden slack.

Crown, Strap, and Clasp

Thread the crown in and out. Genuine threads engage cleanly in half a turn. Fakes often cross-thread or feel loose. On the strap, check stitch density and the buckle engraving, which is usually the weakest point on a replica. Packaging is easy to fake but hard to fake well: box printing, warranty card fonts, and the serial on the card matching the caseback are all worth checking.

Price and Paperwork Sanity

If the price is a small fraction of the market, the watch is not genuine, and no story about an estate sale changes that. Pull recent sold prices for the reference and compare. Ask for a timegrapher reading and macro shots of the movement. When in doubt, have a watchmaker open the case before money changes hands.