Don Wise - The Em based chords you posted are sort of a vague approximation of the sound Bob gets in the song, but not what he was actually doing. I got a PM from a Mudcatter who was at shows in '64 or '65 in the front row and saw Bob playing the song, and watched carefully. I'll quote from his PM below:

"I saw Dylan when he first played these great songs in England.
I was in the front row,happy daze!
The base E was down to D.He starts of in G:550003,back to D,then the run down on the A string.
The "slide"is in Dm,sliding up to Em and back down again.
It's almost like the way he plays Hollis Brown,but there's no dropped D,and no slide.He pulls on the A and D strings while staying in the D shape chord.He doesn't play the bass E,nor the treble E.
But you and I both know that he could change all that in the wink of an eye!"