Fourth gen models didn’t come with a serial - they have nothing at all on the left ear stem (outside of a couple of limited editions).A couple of my pair of Juliets don't appear to have a serial number. This a certain year or generation that didn't have a serial number? One is polished gold lenses, one is x-metal plasma with red lenses and red ear socks?
There weren’t any plasma models with red ear socks so those socks are potentially aftermarket. That or from the Oakley Custom Programme.