Short answer

The IW371411 is a steel Portugieser Chronograph with a silvered dial, gold applied numerals, and a 7750-based automatic movement. It gets faked heavily because there is nothing exotic to copy. No ceramic, no titanium, no in-house calibre. So the tells are all about proportion, finishing, and what you see through the back. If you only have thirty seconds, measure the case thickness.

Case: start with the numbers

The genuine case runs about 40.9mm across and roughly 12.3mm thick, with 20mm lugs. Copies usually land between 13.5mm and 14.5mm, because they are built on a stock 7750 inside a generic case that was never slimmed down. That extra 1.5mm reads as a puck on the wrist. Look at the lugs as well. On the original they curve down in a smooth arc and hug the strap. Copies tend to be flatter and squarer, with tooling marks under the bezel edge you can catch in raking light.

Dial details that give it away

• Applied numerals: solid gold on the original, with crisp polished bevels and a clean shadow line. Copies are plated brass, flatter, and sometimes sit slightly crooked.
• Hands: leaf shaped, gold, brushed on top with polished flanks. Plated steel hands on a fake look grey or brassy at the edges.
• Subdials: chronograph minutes at 12, running seconds at 6. The rings should carry a fine concentric grain, and the small hands should sit level with the ring rather than floating above it.
• Printing: dial text stays sharp under a loupe with no halo around the letters. Fakes blur at the edges, or the line spacing drifts.
• Finish: an even silvered tone. Copies look chalky white in daylight or yellow under warm indoor light.

Movement and caseback

The 79350 is an IWC-modified Valjoux 7750: automatic, 28,800 vibrations per hour, around 44 hours of power reserve. Through the sapphire back you should see striped bridges, polished screw heads, and a rotor carrying the brand engraving. A copy usually shows an undecorated plate, laser etching that looks grey instead of cut, and a rotor that rattles when you turn your wrist. Work the chronograph. Start, stop, and reset it a few times. A healthy 7750 snaps back to zero with a firm click and a steady sweep. A cheap clone stutters, or the pushers feel mushy with too much travel.

Crystal, crown, and hardware

Sapphire front and back. On the original the crystal nearly disappears at an angle because of the anti-reflective coating. Fakes often show a blue or purple haze and a slightly domed profile. The crown should be signed and sit flush against the case with no wobble when you wind it; winding should feel smooth with light resistance, not gritty. The strap is leather or alligator on a signed steel pin buckle, and the engraving is deep and sharp. Shallow laser etching on the buckle is a bad sign.

Papers, price, and the honest test

This reference is discontinued, so a seller claiming brand new current stock deserves a second look. Ask for a caseback photo, a movement photo, and the case and movement numbers. Then price it against the market. A clean steel 3714 trades in the low-to-mid four figures, while copies sell for a few hundred. Listings that sit in between, with no box, no papers, and a no-returns line, are where people get burned. If you can, hand it to a watchmaker and have them open the back and run it on a timegrapher. That takes ten minutes and settles it.