Yeah, this headstock angle-thing is an interesting point.
I'm also in the dark about the headstock slant of the bolt-on versions being identical (or not) with the glued/set neck-versions of Mosrite ...
Not wanting to stray too far from your thread now Michael but have you also noticed the angle of the WHOLE NECK in relation to the Mosrite body? This feature has intrigued me ever since I got my Hallmark 60 Custom this year and I even considered posting a thread on it "comparing notes" but never got round to it. (could't find good "side" photo's to illustrate my observation).
Yes so different to Fender's "flat" design of neck and "scooped out" headstock.
I feel that the slant of the Mosrite NECK could very well contribute to better playability, a fuller sound and longer sustain since the strings can now be situated considerably higher from the body than that of a Fender’s, for instance, as a result of the angled neck placement.
Just for the record, my Hallmark 60 Custom has a glued/set neck -also at an angle to the body- and angled headstock.