It’s a 1960s Omega Seamaster Deville in gold cap, 100% real, the twistoflex bracelet is not Omega its just a cheap junk bracelet that was popular at the time aftermarket. It’s best to put it on a leather strap as those bracelets can damage the watch lugs.
It will have a Calibre 56x series automatic movement and ideally should be serviced before wearing it but the movement is an excellent one, if you take care of it and service it at regular intervals you could hand it down to your grandkids one day.
Have the service done by a good independent watchmaker that has an Omega parts account, don’t have it polished, just cleaned and have the seals changed. It won’t ever be reliably water resistant so don’t get it wet.