"live rock" means so many things.
in the simplest form, live rock simply means it has the bacteria that sustains a salt water aquarium. this happens within a month, and doesnt even require seeding.
some call it live rock when it has corralline, IME this requires seeding, but its accomplished through simple things like adding a single peice of coral which will have some corraline on its base.
and lastly, what some want in liverock, is beneficial hitch hikers, which is why "uncured" LR is actually in demand, this means random critters, and corals that will still be alive and such. some consider that the best part of buying live rock. so much that we buy doesnt even have anything like this though, ussually we are paying so much for some simple corraline algea, and perhaps hair algea or diatom to go wtih it.