Hopefully this thread is not confusing people on boiling.
boiling live rock commonly refers to keeping the rock in the dark to kill off the algae and stuff.
(later edit) OK that could be cooking not boiling.
No actually heating the rock in water above the boiling point. (later edit, and it could now be the actual boiling)
IMHO any copper in the rock will be bioaccumulated (filtered out) as it is released by fast growing macro algaes. And eventually be exported by harvesting. But in the mean time the corralline, turf, hair, macros, etc algae actually in the rock itself can contain copper but usually not at levels high enough to kill off fish. It may affect things like sps corals though.
my .02