Thanks for your effort Rich. The suits do look similar but I wouldn't say they were exactly the same. Also the back of the photo says New York Pavilion, not New Jersey.
This is the best I could do. If you look at the one photo, it's a group with the same attire. I used every combination of keywords I could searching and could find no point of reference. Apparently no one has any information on the band(s) who performed at the Flushing Pavilion during the Fair.
I was rummaging through some old high school pictures this afternoon and ran into this photo. Handwritten on the back is, "Oct. 4, 1965, New York World's Fair, New York Pavilion". I was overseas in October of '65 and never got to the World's Fair. I also have no recollection of ever seeing this photo before. Anyone recognize the group?