The short answer
Omega 3604 is not a famous watch. The number gets attached to a few different things, and the only way to spend money well is to work out which one you are looking at first. Most listings using it sell a vintage-styled Omega case, not a modern model. That matters, because vintage replicas are a different game than a Submariner clone. The cases are thinner, the movements are simpler, and the dial and crystal do almost all the work of making the watch look believable on a wrist.
Pin down which 3604 you want
In practice the number turns up in three places: on vintage reference listings, on movement or calibre listings, and as an internal stock code a dealer invented. Those are not the same product.
- Reference listing: expect photos of a caseback stamp and a case shape you can compare against archive images.
- Movement listing: expect a photo of the movement with the number visible on the bridge.
- Dealer code: expect no documentation at all, just a stock image and a price.
Before anything else, ask for a photo of the caseback and a photo of the movement. A seller who cannot produce both is not selling you a watch you can verify.
What the replica side really sells
Most of what ships under vintage Omega numbers falls into two tiers. The cheap tier uses a Chinese or Japanese automatic (Miyota, Seagull, Hangzhou) in a plated or lightly finished case. The better tier uses a Swiss or Swiss-clone automatic and spends real effort on the case profile and dial print. Neither is a restoration. Both are new watches styled after an old one, which is an advantage: you are not paying for someone else's fifty years of moisture damage.
The checks I run, in order
- Dial print under a loupe. Look for fuzzy edges on the logo and uneven spacing in the minute track.
- Hands and lume. The wrong hand shape is the fastest tell, and mismatched lume color is second.
- Crystal. Vintage-styled models should have a domed acrylic or a well-shaped domed sapphire. A flat slab of sapphire kills the look.
- Case profile. Compare side thickness to photos. Over-polished replicas lose the bevels that give the watch its shape.
- Caseback engraving. Depth and font matter more than the text itself.
- Movement beat. A sweeping seconds hand at 28,800 vph reads smoother than a 21,600 vph substitute.
- Bracelet or strap fit. End links that rattle against the lugs are the giveaway people notice at arm's length.
Where these watches fall short
Vintage is harder to fake than modern, oddly enough. Aged lume that looks right in photos rarely looks right in person. Acrylic crystals scratch, and replacement parts for a replica case are often impossible to source. Movement service is the real long-term cost: a watchmaker charges shop time whether the watch cost eighty dollars or four hundred. If the movement dies, you may be left with a good-looking case and nothing to put in it.
The part sellers leave out
Counterfeit watches are illegal to import into the United States, and customs does seize packages. Trademark law covers the logo and the name, not just the design. Resale value sits near zero because no dealer and no auction house will touch it, and there is no warranty worth the paper it is printed on. If you want the look without the baggage, a sterile-dial homage from a brand like Seiko or a small microbrand gets you most of the way there and you can get it serviced.