I was looking at the Wiki article on the song and mentions it was recorded Nov. 1968 and Nov. 1969.
Now 1969 doesn't surprise me since Bridge Over Troubled Water was released in Jan. 1970, which means all or most of the LP was recorded in 69, and though I've read this twice I still can't get it.
http://en.wikipedia.org/wiki/El_C%C3%B3ndor_Pasa_(song)