Thank you gentlemen. From what I can surmise, it looks like both positions were probably used in 1964. THE LEGEND BEGINS shows it on the primary casting and that is the official publication. However, the photos used could have been pre-production shots. Furthermore, mount location could also have been changed during the production year. This is evidenced by Bob's photo of what I believe to be a later production '64 with newer oil tank and the capacitor mounted accordingly.

Given the above responses, all of which from people that I know are knowledgeable, it looks like both positions were used with the final position (left side frame) finalized in 1965. I've mounted mine on the primary casting.

Thank you all for your input.