Not sure if this is of any help but as a nav in the 70's I was issued with an Omega - model unknown. All I remember about it is that it was less accurate than my £10 Singapore bought Seiko automatic, which I always wore for preference. I have a wry smile when I see people paying £100's for these on ebay (always advertised as "pilots' watches" incidentally, which is right I suppose as they were close enough for pilots but definitely not for navs!). I often wonder if the buyers are disappointed. Never saw a service Rolex though.