I guess these are just array indexes. They are required for linking structures, but actual items are added through functions anyway, i.e. battlescanners are added by function UpdateItemCharges() in XGUnit.uc, as well as rockets. The problem is that default battlescanners are going in 2 pieces (IntConstByte 2Cxx) and thereby easy to change and rockets/smoke grenades are both IntOne (000026) that is hard to change via hex editor.