Sherlock vox12string here...
The other Gibson that had 6 in a line tuning pegs in this period was the Trini Lopez model. There were 2 types, one a thin ES-type with rounded shoulders, a & another fatter version with sharp cutaways.
But this isn't the guitar Brian's got at Manchester '64. I re-scanned that section & as soon as I spotted the little bit of pickguard just to the left of the sergeant's stripes it screamed at me. Burns. Found a pic of a Burns-Baldwin Split Sound Jazz model & there she is . There's a bit of shadow around the headstock which fooled me for a bit but check out that diamond shaped logo on the headstock.
I found the pic & info here [
www.glyphmedia.com]
Here's a pic of Brian from the one-plus-one sessions with a Gibson J-200
And finally one of Brian with an Australian Maton semi-acoustic