It's a WWII era military watch. GCT = Greenwich Civil Time. If you were making a joke, sorry. Notice the mil specs on the case back. There were A LOT of these made by Hamilton, too.
Speedy Sunday! The BLRO got several days of wrist time recently which always makes me long for the Speedmaster. Batter up!
146.017 DeVille. Ca.1969/70. Cal.930 There is a thread here: https://omegaforums.net/threads/146-017-how-many-are-there.52128/#post-894466
You are correct. The minute track was what got my attention and the movement hooked me. Very cool old watch.