The short answer
A fake IW371419 fails four checks: the movement seen through the caseback, the case thickness and lug profile, the finish of the applied numerals, and the asking price. The IW371419 is an IWC Portugieser Chronograph, a 41 mm steel watch in the IW3714 reference family. Every watch in that family runs the same IWC caliber 79350, a self-winding chronograph movement rated at 28,800 vibrations per hour with a power reserve near 44 hours. That shared platform makes the movement and the subdial layout the fastest way to separate a genuine watch from a counterfeit.
What a genuine IW371419 should show
- Case diameter of 41 mm and a thickness near 12.3 mm, with a thin bezel and long, tapered lugs.
- Two subdials stacked on the vertical axis: chronograph minutes at 12 o'clock, running seconds at 6 o'clock. No date window.
- Applied Arabic numerals and feuille hands, with polished bevels that catch light along a single sharp line.
- Sapphire crystal on the front and a sapphire display back, with anti-reflective coating that reads colorless, not blue or purple.
- Caliber 79350 behind the display back, marked with the caliber number, striped bridge finish and a decorated rotor.
- The reference number engraved on the caseback and repeated on the warranty paperwork.
Step-by-step inspection
- Turn the watch over. A solid steel caseback on this reference is a hard stop, because the IW371419 left the factory with a sapphire display back.
- Read the caliber number through the glass and compare it against published photos of the 79350. Look at the shape of the bridges, the finish on the rotor and the position of the balance.
- Check the subdial placement. On a genuine watch the two subdials sit directly above and below the center hand stack; many fakes use a stock chronograph layout with offset subdials or a date at 3 o'clock.
- Start the chronograph, let it run for two minutes, then reset it. A genuine 79350 resets with one firm snap and the minute counter lands on zero.
- Press both pushers. They should travel with even resistance and return under spring pressure without grinding or wobble.
- Measure the case with calipers. Counterfeit cases often run 1 to 2 mm thicker than the genuine 12.3 mm, which changes how the watch sits on the wrist.
- Inspect the dial print with a 10x loupe. The brand name and the country-of-origin text should have crisp edges and even spacing, with no ink bleed or double-struck letters.
- Compare the engraving on the caseback. Genuine engraving is cut deep with clean walls; fake engraving looks shallow, laser-burned or filled with paint.
Movement checks
Ask the seller for a clear photo of the movement before you commit. A genuine 79350 fills the case with no plastic spacer rings, no exposed screws of random lengths and no rough, unfinished edges on the rotor. If the seller refuses to show the movement, or sends a stock photo taken from a catalog, treat the watch as suspect. A watchmaker or an authorized service center can open the case in minutes and confirm the caliber number on the spot.
Price, box and papers
The IW371419 trades in the low-to-mid four figures on the secondhand market, and prices move with the dial code and the completeness of the set. A listing far below the going rate for the reference family is the oldest signal there is. Boxes and warranty cards are easy to copy, so treat them as supporting evidence only. A serial number that does not match the paperwork, or paperwork that lists a different reference, is a problem regardless of how good the watch looks.
Where to get a verdict
Send the watch to an IWC service center or a watchmaker who services the 79350. Ask for the movement caliber in writing and for a photo of the caseback engraving. That report settles the question, and it costs far less than a bad purchase.