Yeah, a lot of us found that rock from liverocks.com arrives with such minimal die off, that no ammonia or nitrite is ever detected.
even with my SeaChem ammonia test kit, which I"m told can be too sensitive and give false positive readings, I never got more than 0.02ppm of total ammonia...and my AP test kit said 0ppm as did the LFS
's tetra brand test kit.
Still good to monitor readings, since its possible for a critter (crab, shrimp) to die inside the rock and cause some elevated ammonia levels...but you'll probably be just fine.
Congrats on the live rock order too. You'll be quite impressed with the quality of Mike's rock.