There were three designs, the AA, AB, and AC. The ticking seems to be only occurring on the AA head - at least last I heard. The AB was a short run, then AC started and continues now.
Read this thread, it explains how to ID the head. I also noticed a louder noise until about 1500 miles.
2013 JKU Sport, billet, auto, 3.73, LSD, 315/75/16 Duratracs on MB 72, 10A springs, Bushwacker flatties
Sold - 2005 TJ, red, auto, 3.73, 33" Duratracs, 4" lift
Ice storm casualty in 2007 - 2003 TJ, green, auto, 3.73, 33" Duratracs, 4" lift