All very interesting but w hilst it was great to hear an early (claimed to be from 1964) recording of EMR with Gord's voice featuring a definite "rasp", as I watched the footage of the trio I could not help thinking that I had seen it before and true enough the stage lighting is manifestly the very same as the BBC used 5 years later for Gord's appearance on their Rolf Harris show, which I very much doubt they specially imported from Canada!
To make my point here is a sample screenshot made from the alleged Mariposa performance that is claimed to be from 1964 on
https://www.youtube.com/watch?v=txSX1-IqIPA
compare that with a screenshot made from the BBC video at
https://www.youtube.com/watch?v=ZFJ5Bj_put0
Furthermore a quick scrut told me that the young fellow on the right playing a bass guitar looks remarkably like a young Richard Dutkiewicz yet Rick did not until 1969 replace John Stockfish (who had apparently joined the orchestra in 1965} at which time he presumably replaced Paul Wideman, who I see nevertheless played bass in a concert in Ottawa on January 27, 1966 but I could not find when Paul had joined so he may well have been on the 1964 Mariposa recording but most certainly it was not Rick.