Guild mini hum?

[Tony Bones]

I'm interested in finding construction details of these. They're humbuckers made by Guild in-house during the 60's. They're smaller than PAF's, are sometimes referred to as HB-1's, but are different from the HB-1's made during the 70's and 80's, (which are actually slightly larger than PAF's.) Obviously not the later Fender made HB-1...

Any info, gut shots, whatever, would be appreciated.