Short answer
Replica Omega 3520 is a search term, not an Omega model. Omega's published caliber and reference lists do not include a 3520 movement or a 3520 case number that I could confirm. Listings that use the term sell counterfeit Omega watches and attach the number as a keyword tag. A counterfeit is not made by Omega, is not serviced by Omega, and carries no Omega warranty.
Where the number comes from
Omega caliber numbers run in blocks. The bumper automatic calibers of the late 1940s and early 1950s use three digits, 330 through 354. Later families use four and five digits, such as the 550 and 560 series, the 1000 series, and the 8000 series. A block that starts at 3520 is not part of those families. Some sellers borrow numbers from case references, movement stamps, or wholesale lot codes. Others invent them. The number in the listing is a tag for search traffic, not a record of a production model.
What a listing claim should let you check
- Movement: caliber number, jewel count, beat rate, and a photo of the movement.
- Case: reference number, diameter in millimeters, lug width, and caseback stamp.
- Serial: the number range and the date it points to.
- Papers: warranty card number and the dealer name printed on it.
A listing that names no caliber and shows no movement photo gives you nothing to verify. Replica sellers cannot supply Omega documentation, because Omega does not issue it for counterfeit goods.
Legal status in the United States
Trafficking in counterfeit goods is a federal crime under 18 U.S.C. 2320. A first offense carries up to 10 years in prison and a 2,000,000 dollar fine for an individual, with higher limits for a business. U.S. Customs and Border Protection seizes counterfeit watches at the border. A personal import of a counterfeit watch is subject to seizure, and CBP destroys the goods. Trademark owners can also sue sellers and buyers in civil court under the Lanham Act.
Risks that follow the purchase
- Seizure: the parcel can be stopped and destroyed, and no refund follows.
- Service: Omega does not service counterfeit watches, and independent watchmakers may refuse the work.
- Parts: a counterfeit movement takes non-Omega parts, and supply depends on the seller.
- Resale: counterfeit watches have no resale market with reputable dealers.
If you want the real thing
Genuine vintage Omega watches with bumper calibers sell at auction and from dealers. The caliber 352 from the early 1950s is a documented movement with a known jewel count and a known service record. Papers, service history, and a serial check separate those watches from a listing that carries the tag "replica Omega 3520."