The short answer

IW329107 is an IWC Portofino Automatic 37 reference: stainless steel, roughly 37mm across, around 9mm thick, self-winding movement, sapphire crystal, leather strap. A replica IW329107 is a copy built outside IWC, almost always in a Chinese factory, and sold through gray-market sites. It is not the same watch. Case finishing, movement, and dial printing differ in ways you can see with a loupe, and the "Swiss super clone" label on a Portofino means very little because no factory puts serious money into this line.

Why this reference is a niche replica

Factories chase volume. The money sits in Submariner, Datejust, Daytona, and Royal Oak copies, because those sell in huge numbers and buyers know the models by sight. A 37mm dress watch with a small production footprint does not get the same treatment. What you find instead:

  • Mid-tier factories that build several references off one case supplier.
  • Cases that run 0.3mm to 0.8mm off the real dimensions, which shows on a 37mm watch.
  • Dial printing that reads fine at arm's length and soft under magnification.
  • Off-the-shelf movements instead of a clone of the IWC calibre.

None of this makes the watch junk. It means the marketing is ahead of the product.

What to compare before you spend

Case and proportions

Look up the genuine numbers first: 37mm diameter, about 9mm thick, and a lug-to-lug that fits a 6.5 inch wrist. Ask the seller for caliper photos. If they only send glamour shots of the dial, they are hiding the profile, and the profile is where cheap cases fail.

Dial printing and finishing

Check the brand wordmark, the "SCHAFFHAUSEN" line, and index alignment at 12. On the real thing, applied markers sit flush and reflect evenly. On a copy they often sit a hair high, and the polish runs one direction across the whole set. If the date window wears a white plastic ring, walk away.

Movement

Most replicas in this size run a Miyota 9015 or an ETA or Sellita derivative. Both are decent and both are serviceable by a local watchmaker. What you will not get is the finishing of the real calibre, and the rotor engraving is wrong. A rotor spin and a look at the balance wheel tell you most of what you need to know.

Caseback and hardware

Reference numbers, serials, and engraving depth are the easiest tells. Compare the font against a photo of the genuine caseback. Then handle the strap: real alligator on a genuine Portofino, embossed calfskin or "genuine leather" on a copy.

The parts the listing leaves out

  • Water resistance. A 50m claim on a replica is a claim, not a test. Assume splash only.
  • Servicing. Independent watchmakers may refuse the work, and parts rarely match.
  • Resale. There is none. You cannot legally resell a counterfeit in the US, and no dealer will touch it.
  • Import risk. US customs law bars importing counterfeit goods even for personal use, and watches are a regular seizure category.
  • Fraud. Selling it as genuine is a crime, not a gray area.

Bottom line

If you want the look of a Portofino Automatic 37 on a budget, a replica can get you close at arm's length. It will not fool a jeweler, it will not hold value, and it carries real risk at the border. Go in with your eyes open, and never pay super clone prices for a watch nobody super clones.