I did some searching...
Could find nothing on google. But I do remember hearing about AH-1 Cobra's, not UH-1 Hueys, downing some Colts near the end of American Invlovment.
I know for certain that A-1 Skyraiders claimed MiG17's in combat at least three times during the war, Its quite possible they shot down a AN2 down in Laos or N.Vietnam on a Rescue Mission.