Short answer

IW545120 is not a reference number listed in IWC's published catalogs. The IW prefix and the six digits match the IWC format. The 5451 block does not appear in current or archived listings. A watch sold as a fake IW545120 copies a model IWC did not catalogue. There is no genuine example to compare it against.

How IWC reference numbers work

IWC writes references as IW followed by six digits, for example IW545408. The first four digits name the family. The last two name the variant: case metal, dial, strap. The Portuguese Hand-Wound 8 Days sits in the 5454 family. Serial numbers are separate. They run six to eight digits and are engraved on the caseback.

Possible origins of the number

  • A typing error on a grey market listing for a 5454 reference.
  • Reuse of a number by a seller who did not check the IWC catalog.
  • Copy of a photo caption from a forum post.

None of these confirm that a watch exists. A number printed on a listing proves nothing.

Checks on a Portuguese Hand-Wound

  • Case size. 43 mm on the 5454 series, measured across the case, not the crown.
  • Caseback engraving. Reference and serial are cut into the metal, not laser printed.
  • Movement. The 5454 uses a hand-wound calibre with an eight day power reserve. A rotor inside means the case does not match.
  • Dial print. Edges of the numerals are sharp under a loupe. Replica print shows rounding and fill.
  • Papers. IWC offers an Extract from the Archives. That document ties a serial to a reference.

Price signals

Steel IWC Portuguese hand-wound watches trade in the thousands of US dollars on the secondhand market. Listings under USD 1,000 that claim genuine origin are not credible. Replica listings run USD 150 to 600. A seller who asks for a bank transfer and refuses a service center check is not a source to trust.

Verification steps

  1. Write down the reference and serial from the caseback.
  2. Compare the pair against the IWC catalog for that family.
  3. Request the Extract from the Archives from IWC.
  4. Book a check at an authorized service center. Technicians verify the movement and the case numbers.

What is unknown

IWC has released many references without public documentation. A reference absent from a catalog page may still exist. That gap is why a service center check carries more weight than any web search. No published list includes a 5451 family as of this writing.