1930s Omega, which ref?

Hi,

I inherited a vintage Omega from my late great aunt. It is a two tone face Omega and I am not sure which model is it. It looks like T17 cal 994 but the crown is not embedded into the case like in the catalogue pic of the 994. Could my watch be 20F?
Here's the catalogue of T17 https://omegaforums.net/threads/omega-ads-catalog-sheets-for-t17-20f-caliber-watches.64350/
I have not opened the watch but it moves well and beside the beaten case, patinated face and broken glass it looks good.
The cool part of the watch is that it belonged to my mothers aunt who got it 1940. I also own the Omega cal 285 owned by the late great aunt's father.

Nice watch! Maybe its a CK 3516?

Couple of relevant threads I was able to dig up that might be of help:
https://omegaforums.net/threads/any-t17-omegas-out-there.47483
https://omegaforums.net/threads/eve...e-difference-between-ck929-and-ck-3516.21176/

Or a CK929?

Thanks, it could be CK929, the measurements seem to be in that ballpark area, but the face is a bit off (but I think there can be variations there)

Looks like my CK 3516