I was going to say the same thing as the other poster about maybe Kerry forgetting who the prez was at the time, but you make a good point. Even though we are only talking a month's difference here, most of the time was under Johnson's admin. He surely would know it was under his presidency then.
Also, his story in the 1986 testimony is completely different from his story in the Kranish story and in Tour of Duty.
Obviously he is lying in one of the stories, and it makes no sense to be lying now about something he was proud of and tried to show off (his secret mission) in 1986.
I should clarify that I mean it makes no sense that he would make up a story NOW about the Cambodia mission if it was real since he was proud of it in 1986.
Obviously either both strories are lies, or what he is telling now is actually the truth instead of the 1986 version.