I am trying to identify and value my father in law's watch. It was given to him as a gift by the Sultan of Oman in circa 1975-6. I've searched the internet but was unable to find anything useful. The automatic watch is by the Swiss brand Century and has 18K 0.750 gold marks. It is a solid gold watch form what I am told. Also as the face has the sultan's emblem as can be seen in the photos.
Unfortunately there are no model numbers or anything to better identify the watch.
Any help would be appreciated.