Im not familiar with this combo

 

There are a few similar ones on google images if you type omega dynamic deville, none of them have a white strap though, they are either black or brown.

I did not check to see if they were genuine, but the fact that more than one image pops up suggests that it was a colour that was sold and as these watches are not exactly setting price records I doubt it is worth faking them

 

I think it's genuine also . Looking at internet and you find a lot of them . Like this . https://poshtime.com/vintagewatches-Omega-DeVille-Dynamic-c.1975-_481.006.php
Price is good but the case has some spots without goldplating .

 

Thanks gents