re: we had an American Naval officer .... [who] often said that things either were or were not in gee. The context led us to conclude he meant agreement

I suspect your conclusion was correct, Churl Pat, but my guess is that the Naval Officer had a musical background and he was using the expression "in G", not "in gee".

The most common of all chord progressions is three chords - often called a "three chord progression". ... The chord for that shown first in major chords are:

C,F,G (C Major, F Major, and G major)

http://snipurl.com/ghhe