I just looked back at some of the earlier posts - one from flickoflash caught my eye:
"Seems you didn't read the tech sheets on how it is done . First the temperatures are dropped to -300 which realigns the molecular structure & then it Is Heat treated after to lock it in."
From basic principles - especially for Face Centered Cubic metals like Copper, the statement above is purely backwards. Generally speaking, changes in a crystal structure are very temperature dependant, happening faster at higher temperatures (especially for FCC metals). This means that changes will happen faster at room temperature than they will at -300. Since (if I recall correctly), the kinetics are quite slow on this kind of thing until you reach a significant fraction of the melting point (expressed in degrees Kelvin) - for Cu, grain growth (which is the primary thing that would affect conductivity for relatively pure Cu) is very slow (almost non-existent) at room temperature. At cryo temperatures, it would be exponentially less.
For most changes in metals - you heat the metal to make the change happen and then cool it to lock it in.
Once again - Steels are a different category because of the mobility of carbon in the iron matrix. Cryo could certainly harden steels, but hardness isn't much of a consideration for most parts of an electric guitar (except maybe the trem).
Rich
P.S. Its kind of fun talking about this stuff again. I left materials a while back & moved to digital television (I'm currently immersed in making DTV work)...