BTW Sandy's comment about COB is between "The Lady" and "John the Gun" (around 38:25 in my (sugarmegs) copy): [Sandy]: "Thanks very much... [interrupted by siren passing by] .. I think we'll be having to wind up now, because COB's coming on very shortly..." COB's upcoming set is also mentioned by the emcee prior to Sandy's encore of "The Rigs of The Time", around 50:57.
Of course even if different originals exist, you would expect them both to have recorded the same thing, unless the taper switched off his/her machine in between songs (or the between-song chat was deleted in subsequent edits). However I remain to be convinced that this fairly obscure show - for which both of Sandy's key biographers could not even get the date right - was recorded not once but twice by different persons. Stranger things have happened, though, I guess :) Cheers - Tony