According to a list of military commendations, Col. Fred A. Hicks served in the US Army (general staff/infantry) from 1960 to at least 1961, and was awarded a medal for meritorious service in 1961.

I would suspect that it was given to him from the army as a gift, given the plaque. Based on this auction listing for a less ornate clock with a similar plaque, it's likely/possible that he worked for the army (or the government) for a long period of time and was given a clock at multiple career milestones.