Cured rock is rock that has been through the cycle. If you are getting cured LR via shipping, then it will have some die off since it has been out of water, so it's not really fully cured anymore.
If you get it from a LFS, wrap it in some wet newspapers and take it home (assuming it is not a long drive) and you can put it right in your tank. You could also keep it in SW for the trip to prevent any die off.