Short answer
The IW371497 is an IWC Portugieser Chronograph, a steel chronograph on the IW3714 platform. Replicas are common because the watch runs a 7750-derived movement that Asian factories already produce. Four checks settle most cases: caseback engraving, movement finish, dial print, and the asking price.
One caveat. IWC has used the IW3714 reference block for many dial variants and limited editions. Confirm the exact variant with IWC or an authorized dealer before you judge one watch against another.
What the genuine watch is
- Case: steel, about 40.9 mm across, about 12.3 mm thick.
- Movement: calibre 79350, a modified Valjoux 7750. 28,800 vph, about 44 hours of power reserve.
- Layout: chronograph minutes at 12, running seconds at 6.
- Crystal: sapphire front and back. Double antireflective coating on the front.
- Water resistance: 30 m.
Check 1: caseback engraving
Genuine engraving is cut into the steel. Letters have depth and a visible edge under a loupe. Fake engraving is laser-etched: shallow, gray, and soft at the borders. Check the reference number, the serial number, and the sapphire display back. The sapphire should sit flush in the ring, not proud of it.
Check 2: movement finish
Look through the display back. Genuine 79350 movements show a gold IWC medallion on the rotor, perlage on the bridges, and blued screws. Replicas use an Asian 7750. The rotor mark is stamped and flat. The screws are painted blue and the slot edges show bare metal. The balance cock is plain.
Check 3: dial and hands
Genuine numerals are applied with polished facets that catch light at an angle. Leaf hands are thin and taper to a point. The subdial rings are cut, not printed, and the print on the dial is crisp under 10x magnification. Fakes show flat glued markers, thick hands, and shallow subdial rings.
Check 4: price
Steel Portugieser Chronographs sold in the range of roughly 7,900 to 8,600 USD at retail. Used examples trade lower. Replica sellers ask 250 to 600 USD. A "genuine" offer at 2,500 USD with no box, no papers, and no service record is not genuine. Weight is a quick secondary check: the steel head runs about 80 to 90 grams. Most fakes come in lighter or noticeably thicker.
What to do next
Ask for the serial number and confirm it with IWC. Ask for macro photos of the caseback and the movement. Have a watchmaker open the case and time the movement on a machine. A 7750 clone will run, but the amplitude and beat error readings differ from a serviced 79350.