Omega Pocket Watch - help with identification

Estimated Omega experts. It is my first thread in this forum and I am very pleased to have found this platform. As many of you before, i need help to identify one pocket watch that belonged to my grandfather. I dont know when or where he bought, but i guess it would be before the 60s. I have also look into many of the previous threads with this same subject, but i didnt see any watch similar to this. I know it is not something fancy or unique, but it would be nice to know a little more about it, with your kind help.

Please see the pictures below. Let me know your comments! 😀 Looking forward to it.

More pics 😀

Thanks Foo2rama for the help.
Thanks Foo2rama for the help. I didnt imagine it would be that old. The 6.5m series you mention is the number 6560482? You said it is from 1923, but it was not necessarily fabricated in 1923, right? I ask it because my grandfather was 15 years that year and I am pretty sure he couldnt afford an Omega with that age. Do you know until when it was on production?
Thanks a lot for the help!

Thanks Dan for the clarification. Do you think it is worth to take to an Omega authorized shop for a restauration? I didnt try to make it work, afraid it could damage the movement.