Are you putting it in a new tank? If you are, you will cycle anyway so if it is not entirely cured then it will be by the time your cycle is complete. If you are adding it to an established tank, you can put the LR into a temporary container and test that water with the rock in it every day for a week to ensure you don't have amonia spikes. If you don't have any, then you are likley safe to add the live rock. If the tank is established, it is usually advised to add the LR in stages instead of a huge addition all at once.
Krash