jpu2166

Well. according to the BOTB book, the heavy gauge strings, which were all that was available in the late 50's did in fact slightly change the neck angle. Read the book. Don't shoot the messenger mate. Lighter gauge strings did not appear on the market until the mid-late 60's with Ernie Ball slinky's.

Apparently the heavy gauge strings used way back in the late 50's caused the original neck angle to lessen due to the strong tension of those heavy thick strings. More can be read about this subject in the book "Beauty of the Burst". Modern string gauges of today are much, much lighter and I would conclude there is far less tension trying to pull on that neck nowadays than with those original 'Bursts. As to the neck angle set at the Gibson factory, a simple email to the factory might give you an accurate answer straight from the horse's mouth.