This operation was, I believe, the SEATO exercise your website refers to , taking place in mid-1964.
At the time, VMO-2 fielded the OE1 (later, the O1-B) "Bird Dog" made by Cessna and the HOK (later, the OH-43) "Huskie" made by Kaman.

For this exercise, there were six observers and at least that number of pilots and HOKs.
We came together on the Philippines Island of Mindoro in late May - the Operation lasted from May 28 to June 13, 1964.  We were co-located with the Operation Headquarters.

The planes were used for observation and for liaison (taxi) service.

This plane, VS-10 (BuNo 139984), was taking off around noon with only the pilot (1st Lt. John Henry Key) and an observer  (2nd Lt. Robert C. "Bob" Yost) aboard. It had risen from the ground, tipped forward and was picking up some speed when a loud report was heard and the plane crashed into a rice paddy dike and the barbed wire we had strung atop it to keep semi-domestic animals out of the area. The pilot and observer were shaken but not broken. The plane was not so lucky. The rotors were very flexible as you can tell from the natural droop shown in the photos. To stiffen them, there were heavy weights in the tips. When the plane hit the ground, the downward momentum of the rotors caused them to chop off part of the fiberglass tail assembly while disintegrating the rotors. The rotor tips were found far from the crash site. In addition, the plane suffered a broken lower pilot's bubble, the left-front wheel was separated and the left-rear wheel punctured the fuselage.

The plane was evacuated to the LPH and returned to MCAF Futema. The official investigation placed the cause of the crash on "carburator icing". The plane was repaired by the squadron mechanics and did fly again.

In hot, humid weather the HOK suffered severe "lift" problems. To safely fly, the load it carried had to be sharply reduced. On this same operation, during an observation mission the same pilot encountered "lift" difficulties with the HOK he was flying. He had to land the plane on a beach and debark his observer-passenger with the promise to return for him later when it wasn't so hot. The observer, 2ndLt Richard M. Cirami, had no choice but to do as instructed. Lt Key, true to his word, returned and retrieved Lt Cirami around dusk.

Marine pilots of this plane called it the "Shuttering Shithouse" for good reason. The vibrations caused by the counter-rotating rotors were so extreme that it was impossible to read a map or make notations on a knee-pad while in flight. At this time (mid-1964), VMO-2 was flying three OE1's in DaNang , Vietnam (using the tail letters of the the helicopter squadron to which they were attached). I've found no evidence that the Marine Corps HOK ever flew in Vietnam.

I've heard of at least a half dozen crashes of the HOK at Camp Pendleton, CA and in Japan with at least four fatalities among them. Pilots I've known who flew this helicopter were universally contemptuous of it.

In the photo above, first panel, you can see a fuel truck and four other HOKs in the background. The ones that can be identified are VS-11, VS-5 and VS-6.

In the third photo , you can see the exercise headquarters tents and a crash wagon. The crash wagon was not needed in this incident.

The photo below is one I took of YS97 (BuNo 136904), an OE1 "Bird Dog" while flying in Vietnam between late June and late September 1964. YS were the tail letters of HMM-162 (Marine Medium Helicopter Squadron) to which the pilots, observers and planes of VMO-2 were attached while in Vietnam. HMM-162 was flying the Sikorsky H-34 "Choctaws" at the time.