Nice story Stubblejumper and good to have you here in the forum. All too often, we read these and the watch has been inherited, so it's great that your father was able to give the watch to you himself.

Scratched plexi is often easily remedied with a quick polish (better that than removing if at all possible on a Monaco, you can search for the words "gasket goop" on here to see what the results can be...), and you might have some luck finding the missing parts with a WTB post on the ChronoTrader forum here.