The baserock that I got sat outside in a storage bin for awhile (same with yours). I just rinsed off the dust and the few bugs that were on there and stuck it into the tank. However, when I had the baserock, I didn't have any LR. So I just cycled the tank with a piece of raw shrimp. After that cycle was complete, I stuck in the LR I bought.
BTW, did you get your tank yet?
-Richer