Authentic or fake?

SkunkPrince

It's probably "real" as far as it goes but the dial was refinished (poorly) and the crown was replaced with whatever the watchmaker had on hand at the time.

If you plan on wearing it with any regularity, I would consider sending it to Omega for service... they will of course use all genuine parts, refinish the dial (again) making it look a lot better, and refinish the case so it looks more like it did originally.

You might also consider keeping it more or less as is if you value the history of it, just changing the crystal because yikes! and replacing the crown for water resistance reasons.

There really is no wrong answer, whatever you decide with this one won't lessen its value.

Spruce

Take it to a local watchmaker. Get him to service it, fit a new generic crystal and a better crown (you can Google to check out what looks right - or he may know) fit a new leather strap, use a jewellers cloth (nothing more abrasive) to give the case a very gentle polish and you’ll have a watch you’ll enjoy wearing.

SkunkPrince

Or a new Omega crystal and Omega crown. If you can share where you are we can suggest watchmakers who are factory-authorized for parts and service.