Nice catch. Very classy dial and it must give a fantastic effect when the light hits.
I've seen this dial before, note that there seems to be a lot of different dials for these early seventies rectangular or tank style models. With and without roman numerals, plain and guilloche etc. It's an uncommon model but I think original as far as I can judge.
Here's another for sale I just found for reference:
https://ticctacc.com/products/omega-deville-art-deco-watch-unisex?variant=47781642273107