I worked in the Instrument Calibration Room at Waddington for a few months in 1968 and all the watches that came through there were Hamiltons with military markings. It was the same later on in 1969 and 1970 at Changi - military Hamiltons with an occasional ancient WW2 issue Omega.
Of course, that may simply mean the the Hamiltons were a load of crap and none of the civvy pattern Timex watches ever went wonky...