The 23767 indicates a Convertible Lemans. It is possible it was a GTO. On the 65s the best way to check is through PHS. If the car has had lower quarter patches, beware. If the seem was cut below the original spot where the GTO emblem was you could sand the metal down and verify only 3 holes (or maybe 2...it was a much smaller emblem). The lemans got about 2 holes per letter, where the gto only had 3 holes. Look for the console and higher options. GTO's typically came with more options, but there are still low option ones there.