Short answer
The IW545198 is a Portuguese Hand-Wound, and fakes of it fail on three things first: case proportions, dial printing, and the movement. Measure the case with calipers, read the dial under a 10x loupe, then look at the calibre through the caseback. If the case measures under roughly 42 mm across, the printing looks dotty or sits unevenly, or the movement is a stock 6497-style hand-winder with no power-reserve pointer, the watch is not genuine. The genuine reference sells new in five figures and used in solid four figures, so a price in the hundreds settles the question before you ever open the box.
What you need
- Digital calipers
- 10x jeweler's loupe
- Digital gram scale
- Bright, diffused light and a clean cloth
- Smartphone camera with a macro function
- A timing app or a watchmaker's timegrapher
Authentication checks, in order
- Measure the case. Take the diameter across the bezel at 2, 6, and 10 o'clock and compare each reading to IWC's published figure for the reference. Replica cases are usually a millimeter or two off, and the error is rarely consistent around the circumference.
- Check the lug profile. The lugs should taper in a continuous curve with sharp, polished bevels that catch light in a single unbroken line. Fake lugs show rounded edges and a bevel that fades out before the lug tip.
- Read the dial print under the loupe. Genuine text is applied in crisp, solid strokes with no bleed into the dial. Look for uneven spacing in "SCHFFHAUSEN"-style lettering, ink that sits thick on one word and thin on the next, and numerals that are not perfectly upright.
- Inspect the small seconds subdial. The subdial must sit exactly on the 6 o'clock axis with even margins on both sides. Measure the gap from the subdial edge to the nearest numeral on each side. Replica dials frequently push the subdial off-center by a fraction of a millimeter.
- Compare hand length and finish. The minute hand should reach the inner track, and the hour hand should end short of the numerals. Look for tool marks on the flat of the hands and for lume that spills over the metal edge.
- Examine the crown. The crown should be engraved deeply and centered, with crisp shoulders. Feel the winding action: a genuine hand-wound calibre winds smoothly with no grit and no slack in the first quarter turn.
- Turn the watch over and study the caseback engraving. Reference and serial numbers should be cut into the metal, not laser-etched on the surface. Run a fingernail across the numbers. Genuine engraving catches the nail; etching feels flat.
- Inspect the movement through the sapphire back. Look for Geneva stripes with even spacing, blued or polished screws sitting flush, and a power-reserve pointer on the movement side. A bare, undecorated bridge with a single stamp mark means the watch is a replica.
- Weigh the watch. Record the number and compare it to a known-authentic example of the same reference. A 5 to 15 gram shortfall usually means a hollowed case or a lighter movement spacer.
- Test the beat rate. Put the watch on a timegrapher and read the amplitude and rate against the calibre specification IWC publishes for the reference. Replica movements commonly run at a different frequency and show a rate that swings widely between positions.
- Check the crystal and its edge. The sapphire should sit slightly proud of the bezel with an even, polished edge and no glue residue visible at the seam.
- Verify the serial with IWC. Request the serial and reference together and ask IWC client service to confirm the pairing. Then check the papers, the warranty card printing, and the box hardware against photos of an authentic set.
Dial details that separate the two
Zoom in on the hour numerals. Genuine examples use applied markers with a polished frame and a lume fill that stops cleanly short of the frame edge. Fakes show a lume fill that touches the frame, a slightly thicker frame, and a faint halo where the adhesive squeezed out. Under raking light, the genuine dial has a fine, even grain; replica dials look flat or show a faint orange-peel texture.
Red flags that end the conversation
- Seller refuses a caliper measurement or a caseback photo
- Price far below the current secondary-market range for the reference
- Serial number that does not match the reference on the caseback
- Warranty card with printed, not stamped, dealer details
- Movement photos taken from a catalog rather than the actual watch
- Pressure to pay by wire or peer-to-peer transfer with no return window
If you already bought it
Stop wearing the watch, photograph every angle, and keep the listing, messages, and payment record. Take it to an IWC-authorized watchmaker for a written opinion, then open a dispute with your payment provider using that document. Selling a counterfeit watch is illegal in the US under trademark law, so a seller who shipped one has no defensible position.