Because I couldn't view the back of this photo, I conducted various copyright searches on the UPenn site to try determining if any copyrights had been registered.
I searched the complete volumes for film and artwork for the years 1965 to 1969. Desilu Productions registered only w:The Lucy Show and w:Yours, Mine and Ours (1968 film) in conjunction with Walden Films. NBC registered only one still image-a color slide from Bonanza of Ben Cartwright on a horse.
Nothing turned up when I searched Star Trek for the years 1965 through 1969 in either film or artwork.
There's no evidence of copyright for this time frame from either production company.