Quick answer
A replica of reference IW371480 usually fails in three places: the dial printing and subdial spacing, the feel of the chronograph pushers, and the finish of the movement behind the sapphire caseback. Work through those three before you look at anything else. Strap stitching, crown engraving, and box printing are supporting evidence, not the verdict.
Reference IW371480 belongs to the IWC Portugieser Chronograph 3714 family, a stainless steel watch with a 40.9 mm case and a Valjoux 7750 based calibre 79350. IWC later moved the line to the in-house calibre 69355, so movement architecture is one of the clearest separators between a genuine 3714 and a copy.
Prerequisites
- A 10x loupe or a phone macro lens
- Digital calipers
- Reference photos of an authentic IW371480 shot at the same angle and light
- A spring bar tool
- Access to a watchmaker if you want the caseback opened
Step-by-step checks
- Measure the case with calipers and write down width, thickness, and lug spacing.
- Compare those numbers against IWC published specifications for the 3714 family. A case that is a millimeter fat or thin is the fastest tell.
- Place the dial under the loupe and read every printed element, including the IWC signature, the Schaffhausen line, and the numerals.
- Check the edge quality of that printing. Genuine text sits flat with sharp borders, while replica text frays and thickens at the corners.
- Match the subdial positions to your reference photo. The 30 minute counter at 12 and the small seconds at 6 must sit on the vertical axis with even gaps to the hour markers.
- Study the hands. Leaf shaped hands should taper to a clean point with a polished bevel and a consistent surface finish along the full length.
- Press the upper pusher to start the chronograph, press it again to stop, then press the lower pusher to reset.
- Note the travel and the sound of each pusher. Firm, short, and repeatable is correct. Mushy or grinding travel points to a cheap module.
- Remove the strap with a spring bar tool and inspect the lug holes, the spring bars, and the polished and brushed transitions on the case flanks.
- Turn the watch over and examine the movement through the caseback display.
- Compare the rotor engraving and the bridge finishing to your reference photos. Replica finishing is often stamped or painted rather than machined.
- Read the caseback text with the loupe and confirm the reference number and serial number match the seller paperwork.
- Set the date and advance it past midnight to watch how the disc turns and how the numeral sits in the window.
Common red flags
- A price far below the current market for a steel Portugieser Chronograph
- A seller who will not meet at an independent watchmaker for an inspection
- The same serial number appearing across several listings
- Date numerals in the wrong font or sitting off center in the window
- Rotor engraving with uneven depth or paint fill
- A crystal with a heavy blue tint and no visible anti-reflective effect
- Caseback text that is shallow, blurry, or inconsistent in letter spacing
What the reference number tells you
The 3714 family ran on the calibre 79350, a modified Valjoux 7750 with a modular chronograph layout, while later Portugieser Chronographs use the in-house 69355. If a watch is offered as an IW371480 but the movement layout, rotor text, or pusher feel belongs to a generic Chinese chronograph, the reference number on the caseback proves nothing.
Before you buy
Counterfeit watch sales are illegal in most markets, and a fake carries no manufacturer service support, no parts availability, and no resale value. The only reliable protection is a documented service history, a watchmaker inspection, and a seller who accepts a return period long enough for that inspection to happen.