Serial number: 53056717
Article ref: 36121020
Serial number matches what the watch should be. Nothing else jumps out as a concern.
Not the OP, but curious: What is that 'article ref'? That doesn't google to anything, is it a reference to something in the Omega database that isn't public?
Do you know the reference # of this watch? Closest I could find was 157.0032, but as I said, the rotor doesn't match, and none I see photos for have the serial number on the outside of case back.