I noticed that in the episode SAVAGE CURTAIN, Surak - the father of all that Vulcans hold near & dear - was a switch-hitter, offering up the Vulcan Salute both ways. So, this confusion seems to have cropped up from the very beginning ...
Right Hand, "Live Long and Prosper"
Left Hand, "Prosper and Live Long"?
Or,
Left Hand, "repsorP dna eviL gnoL"?
