I'm sure you realize there IS no "correct" olive drab color for a CJ-3A, as they were never factory painted that color (I know a few rare military CJ's exist, but that's not the norm)... Olive drab was used primarily by the military.
Chances are a previous owner painted it OD (as is mine) and with all the various shades of OD out there, it would be a real shot in the dark for any of us to advise you what color you have.
Carlsjeep's suggestion of getting a part matched is probably your best bet. �If you want to reshoot the whole Jeep, then your options increase. �