Help with a 1803 confetti that I’ve been offered

[mlg6613]

I’ve been offered a 1969 serial 21… naked day date 1803 in very good conditions but the only ick is that the outer part of the clasp (the oysterclasp) was changed to a steel one and the owner doesn’t find the original part (it was his father’s watch). Everything else including the deployment part is 18k, I’ve seen the watch in person, the hallmarks and 750 and 18k stamps are very visible.

The watch was serviced in a RSC a couple of years ago and it’s running smoothly. They are asking for 9500 slightly negotiable.

It would be my first vintage watch on my collection and I’m very enthusiastic about it. Please I need help with anything any tips for this kind of watch, thank y’all!