Continuity mistake: Just after the announcement that General MacArthur is coming, Trapper puts on his sunglasses, then the shot switches to Henry walking, and in the background Trapper is putting his glasses on again.
Visible crew/equipment: As Col. Whiteman leave Sentry Post 1, where Klinger is, the boom mic is reflected on his helmet.
Answer: It is actually Cencompac for Central Command of the Pacific. It is like the headquarters for all military activity in the Pacific Region (Japan, Korea, Okinawa, etc. The newer version of that is United States Pacific Command (USPACOM).
EMTurbo
And the abbreviations were used mainly by the Navy. Especially CENCOMPAC.
Https://en.wikipedia.org/wiki/United_States_Indo-Pacific_Command.