The call sign used for the 1964 NY World's Fair was "W2USA" not k2usa.
K2USA (and AA2USA) is the call sign associated with Fort Monmouth, NJ Home of the U.S. Army Signal Corps.
Google is your friend and found this link ...http://126.96.36.199/w2usa/history.htm
... that details the history of W2USA and mentions the 1964 World's Fair but NO pix provided.
This link has NYWF64 info: http://www.nywf64.com/index.html
and here's the Coke link: http://www.nywf64.com/coke04.shtml
plus 1965 link: http://www.nywf64.com/coke05.shtml
" ... Another aspect of the Coca-Cola pavilion is a communication center installed by the American Radio Relay League, the national non-profit membership association of 100,000 amateur radio operators which will celebrate its 50th anniversary during the opening of the Fair. Amateur operators, upon presentation of credentials, will be allowed to broadcast from the studio to other amateurs throughout the world.
Educational information regarding the scientific hobby will be available. Visitors to the pavilion will be able to watch and listen in on these foreign communications.
A USO World's Fair referral and information lounge to accommodate military personnel and their dependents will occupy 1,110 square feet of space in the exhibit. Plans call for a direct tie-line between the USO Times Square Club and the USO World's Fair Club. It is estimated that one million American and Allied Service personnel and their families will use the facilities during the 1964-1965 seasons."
But NO Pixs.
Since the ARRL installed the communications center, they might have pixs in archive of unpublished pixs. Did a ARRL search and found in the Aug 1965 QST pixs of the 1939 World's Fair Station but NOT the 1964 one? Strange they did not blow their horn on this event in QST?
Finally, found that Hallicrafters sponsored K2US via this link:http://www.worldsfaircommunity.org/topic/5403-the-original-k2us/
showing pix of K2US "VHF Room" station.
The 1964 New York World's Fair was my 8th grade class trip. Time sure does fly!
Best I could do - Good Luck.