Short Answer
A fake IW329079 gives itself away in four places: caseback engraving depth, dial printing and date alignment, movement finishing, and the feel of the crown. A genuine IWC shows sharp, even laser engraving on the caseback, dial text with clean edges and no ink bleed, an automatic movement with striped plates and no tool marks, and a screw-down crown that seats in three or four smooth turns. If any one of those four checks fails, stop and get the watch opened by a watchmaker before you pay.
Prerequisites
- A 10x loupe or a phone with a macro lens
- Reference photos of the genuine reference from the maker's own catalog
- Calipers or a digital scale
- A timing app that reads beat rate
- Access to a watchmaker if the caseback is solid
Step-by-Step Checks
- Turn the watch over and read the caseback under the loupe. Compare the reference number, case number, and logo against a catalog photo. Fakes show shallow cuts, rounded letterforms, and engraving that sits off-center.
- Measure the case diameter and thickness with calipers, then weigh the head. Replica cases run thick and light because the alloy and the caseback geometry differ from the original.
- Inspect the dial. Applied indices should have polished bevels and level lume fill. Text should be crisp with no shadowing or bleed. The date window should have a beveled edge, and the date font should match the dial font.
- Check date alignment. Set the watch to a single-digit date such as the 8th. On a fake, the numeral sits high, low, or crooked in the window.
- Work the crown. A genuine screw-down crown threads smoothly and seats in three or four turns. Grinding, wobble, or a crown that bottoms out in one turn points to a copied case tube.
- If the reference has a rotating bezel, turn it through a full circle. Clicks should be firm and evenly spaced with no side play.
- Watch the seconds hand for a full minute. Most IWC automatics run at 4 Hz, which shows eight small steps per second. A stuttering sweep or an audible tick suggests a low-beat clone movement.
- Examine the bracelet and clasp. Links should move without rattle, end links should sit flush against the lugs, and clasp engraving should match the caseback in depth and font.
- Have the caseback opened. Look for signed bridges, striped or circular finishing, blued screws, and a rotor with correct engraving. Replica movements show stamped rotors, rough edges, and mismatched jewel settings.
- Verify the case number with the maker or an authorized service center. A serial that returns no record, or a case number that belongs to a different reference, settles the question.
Common Red Flags
- Papers printed on stock card with generic fonts
- A box that closes with a loose lid or a wrong-color interior
- Serial numbers engraved over a brushed surface instead of a prepared flat
- Lume that glows a different color or fades within minutes
- A seller who refuses an in-person inspection or a watchmaker's opening
Bottom Line
No single check proves a watch is real. Four or five checks in agreement do. If the engraving, the date alignment, the crown feel, and the movement finish all hold up, you are looking at an honest reference. If one of them fails, walk away and spend the money elsewhere.