Here is a link to a website that shows when serial numbers were produced
http://chronomaddox.com/omega_serial_numbers.html
Unfortunately it isn’t an exact science, but it’s something to use.
You can get an extract of the archives, which gives an exact date of production. But that takes time and costs $, so you can’t do that for each watch you are thinking about buying.
You can tell with a Seiko to the month, and that’s what I got for my brother’s 50th. A nice collectible dive watch. 👍
Longines also provides free extracts from the archive if you send them photos. Usually takes just a few days.
