I have a similar question, though looking at all the photos, I find it to be incredibly inconsistent. I saw quite a few "Seamaster", "Seamaster Automatic" and "Seamaster Deville". I suspect that over the years they changed the inscription on the dial quite a few times. These dress watches aren't 'valuable' or popular enough seemingly for anyone to have done the effort to catalog them all.
Apparently it was ~1967 (
https://www.swisswatchexpo.com/thewatchclub/2017/05/07/the-history-of-the-omega-de-ville/) And (
https://www.omegawatches.com/en-us/chronicle/1967-the-de-ville-is-born) that "De ville" as a label was split off of "Seamaster" and would have been around on its own.
So in general: Particularly based on the consistant inconsistency online with these, and the one that Passover found, I don't have a reason to believe that it is a fake/repaint/etc.
It seems like a gorgeous watch that your dad cared for enough to give to you, so it is one you should wear proudly! Get a good sympathetic service (meaning, one where history is preserved when possible), and wear it and think of your dad.