The short answer for anyone typing fake IW545142 into a search bar: the top pick is a movement and caseback inspection, because the movement is the one part of a watch that a counterfeiter cannot reproduce at low cost, and the caseback numbers are the one part that can be checked against a manufacturer record. The criteria below are ranked by how much weight each deserves, in this order: calibre and movement finish, case and bracelet finishing, dial print and hand finish, caseback engraving of reference and serial, then box, papers and service history. Work them in that sequence and most watches resolve in under an hour.
What the String IW545142 Actually Means
Reference strings in this family are manufacturer reference numbers, not model names. The leading digits identify the reference family; the trailing digits usually point to a case metal, dial variant, or market configuration inside that family. A frequent counterfeit pattern is a caseback carrying a reference the seller copied from a photo, paired with a dial variant and case metal that belong to a different variant of the same family. So the first step is deciding which single variant the watch claims to be, then testing every component against that one claim instead of against a general impression. Manufacturer records and authorized service centers are the reference of record. Marketplace listings and forum threads are not.
Check One: Movement and Calibre Marking
Cost shows in the movement. Watches at this level use a finished calibre with signed bridges or rotor, a regulated balance, and finishing that survives a loupe. Replica movements are often generic Asian calibres with a decorative plate added to imitate a signed movement, and the giveaway is usually under the decoration, not on top of it.
- Pros: catches most fakes without any paperwork; a watchmaker can complete the check in minutes; visible through a display back without opening the case.
- Cons: needs someone who knows the expected calibre for that reference; a solid caseback must be opened, which carries risk; franken watches pair a genuine movement with a fake case, so a clean movement is not a clean watch.
Use this check first on any watch with a display back. For a solid caseback, budget a watchmaker inspection before money changes hands.
Check Two: Case and Bracelet Finishing
Case profile, lug geometry, and bracelet end link fit are expensive to copy well. Sharp edges, wrong lug curvature, inconsistent brushing, and end links that rattle against the case tend to appear under raking light.
- Pros: fast during an in-person inspection; weight and balance give useful signals; bracelet clasp engraving and spring bar quality add evidence.
- Cons: cases get recased and refinished, so a correct looking case proves little alone; polishing blurs original geometry; photos hide finishing details almost entirely.
Best for hands-on viewing. For an online listing, request macro photos under raking light and compare them with catalog images of the exact variant.
Check Three: Dial, Hands and Typography
Font weight, letter spacing, applied marker alignment, and hand finishing are the details people photograph most, which also makes them easy to compare.
- Pros: comparison material is abundant; applied markers and hands reveal plating and finishing quality; misaligned date windows and windows with sharp inner edges are common tells.
- Cons: dials get swapped, so a genuine dial on a fake case is a known pattern; camera processing and lighting change how print looks; dial variation across production runs creates false alarms.
Treat the dial as supporting evidence. It rarely settles a question on its own.
Check Four: Caseback Engraving, Reference and Serial
Engraving depth, font, and serial placement either match the reference record or they do not, and the numbers themselves can be verified.
- Pros: numbers are checkable against the manufacturer; mismatched reference and serial end the conversation; engraving style is hard to match on older references.
- Cons: laser engraving equipment is available and inexpensive; engraving gets added or altered; service casebacks replace originals; records for older watches can be incomplete.
Use this as a confirmation step after the movement check, and verify the numbers with the manufacturer or an authorized service center.
Check Five: Papers, Box and Service History
An invoice with a matching serial, a stamped card, and a service record create a chain of ownership that is useful once the physical checks pass.
- Pros: a documented service history supports the movement findings; matching numbers across documents and caseback are a strong signal; service paperwork often lists the calibre.
- Cons: paperwork is reproduced often; a genuine box says nothing about the watch; sellers sometimes withhold serials for privacy, which is reasonable but limits verification.
Use documents to confirm a watch that already passed inspection, never as the first filter.
A Practical Order of Operations
- Identify the exact variant the watch claims to be.
- Ask for the reference and serial, then compare them with the claimed variant.
- Request macro photos of the case, dial, and caseback under raking light.
- Have a watchmaker inspect and, if needed, open the movement.
- Verify the numbers with the manufacturer or an authorized service center.
- Match the documents to the verified numbers.
- Walk away if any step is refused or delayed.
Bottom Line
For a buyer checking one listing, the movement plus caseback route is the top pick, because it combines a physical tell with a checkable record. For a collector building a set, the same order applies but the dial and case checks gain weight, since variant accuracy matters more than a single watch passing. For a seller trying to price a watch, a watchmaker's written inspection report answers more buyer questions than any set of photos. Note that in the United States, trafficking in counterfeit trademarked goods is illegal, so a watch that fails these checks is a legal exposure as well as a financial one.