5.3 have two different style head bolts and some have three different style head bolts?

From reading in 2004 some 5.3 have two different style head bolts and some have 3 different style head bolts. There is not a clear explanation as to when this occurs and in what engines. I am trying to order all parts prior to me going home after my work time is up offshore. Is there any way that we can differentiate this issue? Being it is a 1999 truck and a 04 5.3.