I have what I think is an 1920s Omega vintage tonneau in 18k and I need a new crystal for it.

Here's my problem. I cannot find the case number on the inside back of the case, but I found what seems to be on the back of the case.

The first photo is of the inside back of the case, the second is the back of the case, and I'm throwing in a photo of the movement last with the movement number for good measure.

What case design? What is the caliber?

Do I even have a real deal watch here?

Thanks in advance!

 

You have a real deal. The case is a correct one produced in France and fitted with a 1920s Omega movement made in Switzerland.
The caliber number (26.5 family?) will be stamped on the main plate under the balance wheel

The watches at that time didn't have model names except for a very few lines.
If you still have the old crystal a proper watchmaker may be able to make one for you, this would not be an "of the shelf" item.

A pic of the dial would be nice.