Ah, Californicated, you never fail to amaze

WUT? CA Supreme Court says the issue of the constitutionality of the law was not before it because no constitutional challenge was made.
and

WTH?  Oh yeah:
Attorneys for the state acknowledged in court documents that microstamping technology is “emerging,” but they said lawmakers often enact laws to force industries to innovate. They warned a ruling in favor of gun makers could take away that power.
"The tech to do this doesn't exist, but if we push hard enough maybe it will!"  The Magic Underpants Gnome Theory of Law...