Omega SMP - Engraved number on case back?

[TurboTapin]

I recently purchased an Omega SMP 2531.80. Dated 99. I have this strange number engraved on the case back that I have not seen before. I'm reading out the number as 29724H67. I believe it's a part# due to other Omega part numbers starting with 2972.

Any thoughts? I was presuming someone engraved it after something was replaced but I cannot find any reference to that number.

Thanks,

 

[Jones in LA]

It looks more like a watchmaker's notation to me, and usually, only the watchmaker understands what it means. There is probably an entry in their work ledger that corresponds to this number.

Edited: Feb 19, 2024

 

[Archer]

Yep, watchmakers service marking...