There are some King Biscuit vinyl discs are out there.  However, all the many boot versions I've heard have been from a source taped off the radio.  A lossless version from the Vault would be direct from the masters and sound superior to anything out there and would not have any of the distortion, clicks and pops that even a clean King Biscuit vinyl record would bring. 

Keeping my fingers crossed that this will be one of the first ones made available.  Randy Rhoads at his best!  R.I.P.