Teading the thread above, my above watch was purchased in Darwin Australia in 1986.
I had “18k Gold applications” on alternate links and they are now severely tarnished - some parts almost blue, and spoils the look. ( I did not use it for over 15 years, as it was really a dress watch and not really water resistant despite Omega’s claim it was good to 30m). However , looking at the comments from Periwhuskey above ( who bought a similar one the same year, 1986, in Brisbane Australia, it may be mine is gilt and hence the tarnishing over the years.