Top pick: a hands-on inspection by an IWC-trained watchmaker. It is the only check that reads caseback engraving, movement finishing, and case geometry in the same session, and it sets the standard the other checks are ranked against. The criteria are case geometry, dial printing, movement and caseback detail, documentation, and the legal and resale position of the watch. Confirm every reference-specific number against IWC's own catalog, because IW545178 sits inside the IW5451 group and that group covers more than one configuration.

Case Geometry, Lugs, and Crown

A counterfeit case is close on paper and wrong in the hand. Replica makers copy a diameter from a listing, then miss the details that decide how the watch wears.

Pros

  • Fast to check with calipers and a loupe, no disassembly required.
  • Catches the common replica faults: soft lug edges, an over-polished bezel, a crown sitting proud of the case.
  • Lug width and case thickness are numbers you can compare against the published specification.

Cons

  • Refinishing on a genuine watch can mimic replica wear patterns, so a polished example proves nothing.
  • Calipers alone say nothing about lug curvature or spring bar fit.

Use this check first when you shop online and only have photos. Ask for a straight-on profile shot and a lug-to-lug measurement with the caliper visible in frame.

Dial Printing and Applied Markers

The dial is where counterfeiters spend the most effort and where they still lose. Font weight, letter spacing, and the relief of applied markers are hard to copy at scale.

Pros

  • Raised printing and mismatched font weight show up in a phone macro shot.
  • Marker polish and hand length are quick comparisons against catalog photography.
  • No tools needed beyond a loupe or a decent zoom lens.

Cons

  • Service dials and relumes create legitimate variation that looks wrong.
  • Phone cameras flatten gloss and distortion, so a photo can hide a fault or invent one.

Use this check to filter listings before you travel to see a watch. A straight-on dial photo taken at an angle to the light will show marker depth and print relief.

Movement, Caseback, and Engraving

Movement finishing is the hardest thing to fake at a low price point. Stripes, chamfers, and engraving depth are machine work, and machine work leaves signatures.

Pros

  • Engraving depth and edge crispness are visible under 10x magnification.
  • Winding feel, crown action, and power reserve behavior give you data without opening the watch.
  • A service record from an authorized center settles the question faster than any visual check.

Cons

  • You cannot inspect a movement through a solid caseback, and many sellers refuse to have a watch opened.
  • Some counterfeit movements are finished well enough to fool a generalist.

Use this check when the watch has a display back or when the seller will meet at a watchmaker's bench. If neither is true, price the uncertainty in or walk away.

Boxes, Papers, and Reference Data

Packaging proves nothing. Boxes, hang tags, and warranty cards come out of the same supply chain as the watches.

Pros

  • Serial and reference numbers on the paperwork can be cross-checked against the case.
  • A dated service invoice from an authorized center is meaningful evidence.

Cons

  • Replica packaging is convincing and cheap to buy on its own.
  • Genuine papers get lost and forged in equal measure.

Use documentation as a secondary check only. It should never be the deciding factor.

Legal and Resale Position

A fake IW545178 carries problems no visual check resolves. Counterfeit watches can be seized at the border, they cannot be serviced by the brand, and they have no resale market outside the counterfeit trade. Trademark law gives brand owners the right to stop confusingly similar goods, and that exposure falls on buyers and sellers alike.

Pros

  • Knowing the legal position protects you from a loss you cannot recover.
  • Genuine watches can be serviced and hold value, which changes the real cost of ownership.

Cons

  • None for the buyer. The downside sits entirely on the counterfeit side.

Use this section to decide whether the reference is worth owning at all. If the budget will not reach a genuine example, a documented watch from another maker is a cleaner purchase than a counterfeit.