Mysterious omega reference 2575-1

During my last trip in Rome, I bought blindly one of my favourite type of Omega watch, a manual winding oversize that measure 38,9 mm.
Arrived at home I opened it in the knowledge that surely I would have found some negative surprise, but i discovered that this watch have a mysterious reference 2575-1, searching on internet I haven't found any information about this watch.

The watch has been evidently overpolished on the back and is moved by a 269 movement, the case have a particular lugs, large down-turned lugs with substantial steps.

I will be very grateful to any person that can help me to collect information about this reference, thanks in advance for the help.

Here you can find some picture for reference.

Any suggestion to find information about that watch?

Or try to find 2535 or 2565

Thanks for your reply I have two 2505 and is completely different case.

Nothing found with 2535 or 2565, the only reference that have the same case and lugs but with smaller size is the 2488