Omega early 1900's pocket watch marks...

[Raymondo5508]

Hi,
Can any of the members please let me know what the small triangle shape mark represents on the inside of the caseback of this Omega gun metal pocket watch.
Cheers Russell.

 

[pilotswatch]

Hi, Curiously, it looks to me as an upside down V « five »
Is it a Omega case ?

 

[Raymondo5508]

Hi,
Yes it's an Omega case as per new picture..
Could be an upside down 5....

 

[pilotswatch]

Maybe something to do with reference to months or case batch (lot)
This one has a K