I remember taking MY oath May20,1958 and it went something like this:
“I, A.B., do solemnly swear (or affirm) that I will support and defend the Constitution of the United States against all enemies, foreign or domestic; that I will bear true faith and allegiance to the same; that I take this obligation freely, without any mental reservation or purpose of evasion; and that I will well and faithfully discharge the duties of the office on which I am about to enter. So help me God.” This version remained in effect until the 1959 adoption of the present wording.
Found at: http://www.history.army.mil/html/faq/oaths.html
Prior to discharge we were given instruction to the changes made but did not have to reaffirm the oath. Active duty completed after Cuban Crisis, extension.
Just a guess but I would think these seals that are meeting 0 took the oath well after 1959.