Hi,
Our cured rock is free from decay and has cycled, so normally you can put this in an established tank, but when you have it shipped, it's possible to get some die off which can cause some ammonia spike and when you stack rock, you can kill some of the rock and cause some ammonia.
So you can do it, and I have added direct to a tank several times, but there is always that small percentage change that you can crash your tank. So if you have fish and corals, i would recommend putting in a container for a while and then just moving one or two pieces over at a time, just so you don't shock your system.
thanks