The short answer
"iw545173" is not an IWC reference number. It is a run-together version of IW5451-73, meaning the Portuguese Hand-Wound family (ref. 5451) with a particular dial and case variant. IWC prints its references with the prefix and a hyphen, so any page spelling it as one word is a reseller listing, not a factory document. When you search for a fake iw545173, you are shopping for a replica of a 44 mm hand-wound Portuguese: small seconds at 9, leaf hands, applied numerals, a thin polished bezel and long lugs. That is the whole target, and knowing it makes the rest easier.
What the genuine piece does well
The case is the giveaway. Real ones have a mirror polish on the bezel and lugs that turns into a soft satin along the case sides, with a crisp line where the two meet. Dial printing is thin and hard-edged, numerals sit level, and the small seconds hand is the right length, reaching toward the track without touching it. Sapphire on both sides carries an anti-reflective coating, so the dial stays legible from almost any angle instead of going milky under a lamp.
Where replicas fall short
- Dial print. Replicas thicken the text and round off corners. Under a loupe the numerals look painted rather than stamped.
- Subdial. The small seconds hand is often too short or too thick, and the ring it sweeps can sit flat where the original has a slight step.
- Case finishing. Look at the lug tips. Real ones taper to a clean edge; cheap ones stay blunt and slightly swollen.
- Crystal. Single-sided AR coating is common, which is why so many replica photos show a washed-out dial.
- Caseback engraving. Depth and font weight are usually off, and the reference text can be the wrong size next to the logo.
Movement, honestly
This is where the money goes. A true hand-wound Portuguese has a movement built to be wound daily, with a smooth crown feel and a seconds hand that never stutters. Most replicas get there by stripping the rotor from a thin automatic, or by dropping in a cheap hand-wound caliber. Ask for a video of the watch running and being wound. A grinding crown or a jumpy seconds hand tells you more than any spec sheet. If a seller claims the power reserve matches the original, treat that as marketing until someone shows you a timed test.
Price sense
Replica pricing for a hand-wound Portuguese sits in the low hundreds of dollars for a decent build. Four-figure asking prices are inflated. Genuine secondhand examples run into the thousands, and that gap tells you which category you are in without opening the case.
Checks I would run before paying
- Video of the seconds hand sweeping for a full minute.
- Close-up photos of the dial text, the subdial, and both lug tips.
- A clear movement photo, not a stock image pulled from another listing.
- Caseback and crown shots, since these are the easiest parts to get wrong.
- A written return window, and how the seller handles a watch that arrives dead.
Bottom line
A fake iw545173 can look close in a photo at arm's length. It will not survive a loupe, a winding feel, or a jeweler's bench. Buy it as a look, not as an investment, and judge the seller's willingness to send real photos and video before you judge the watch.