Yeah, in item_kinds1.txt you count how many items there are starting from 0 instead of 1. I think morgh's editor shows the index. If you want to get the ending item's index, you can use the item count at the top of 'item_kinds1.txt' below 'itemsfile version 3' and subtract 1 from it.
4
2133 2 72057594037927941 144115188075856184
2120 3 72057594037927942 144115188075856184 96
2110 2 72057594037927942 603
2106 2 72057594037927942 1 3
4 - 4 Statements
2133 2 72057594037927941 144115188075856184
2120 3 72057594037927942 144115188075856184 96
2110 2 72057594037927942 288230376151712346
2106 2 72057594037927942 1 3
menu_cheat_find_item 0 {!}Current_item_range:_{reg5}_to_{reg6} none 4 2133 2 72057594037927941 144115188075856184 2120 3 72057594037927942 144115188075856184 96 2110 2 72057594037927942 288230376151712346 2106 2 72057594037927942 1 3
mno_cheat_find_item_next_range 0 {!}Move_to_next_item_range. 6 2105 2 144115188075856184 96 4 0 30 2 144115188075856184 288230376151712346 2133 2 144115188075856184 0 3 0 2060 1 864691128455135257 . mno_cheat_find_item_choose_this 0 {!}Choose_from_this_range. 9 1532 1 360287970189639684 2120 3 1224979098644774912 144115188075856184 96 2110 2 1224979098644774912 288230376151712346 2121 3 1224979098644774913 1224979098644774912 144115188075856184 6 3 1224979098644774914 0 1224979098644774913 2120 3 1224979098644774915 144115188075856184 1224979098644774914 1535 3 360287970189639684 1224979098644774915 1 3 0 2042 1 360287970189639684 . mno_camp_action_4 0 {!}Back_to_camp_menu. 1 2060 1 864691128455135255 .
[id], [flags], [text], [mesh name], [num of statements/operations], [[operations]], [num of menu options]
[[option id], [num of operations], [[condition operation]], [option text], [num of operations], [[consequence operation]]]
(assign, reg5, "$cheat_find_item_range_begin"),
(store_add, reg6, "$cheat_find_item_range_begin", max_inventory_items),
(val_min, reg6, "itm_items_end"),
(val_sub, reg6, 1),
4 - 4 Statements
2133 2 72057594037927941 144115188075856184
2120 3 72057594037927942 144115188075856184 96
2110 2 72057594037927942 288230376151712346
2106 2 72057594037927942 1 3
# Inside "game_event_simulate_battle" in "module_scripts"
# center defeated block
(party_get_num_attached_parties, ":num_attached_parties", ":root_attacker_party"),
(try_for_range, ":attached_party_rank", 0, ":num_attached_parties"),
(party_get_attached_party_with_rank, ":attached_party", ":root_attacker_party", ":attached_party_rank"),
(party_get_num_companion_stacks, ":num_stacks", ":attached_party"),
(assign, ":total_size", 0),
(try_for_range, ":i_stack", 0, ":num_stacks"),
(party_stack_get_size, ":stack_size", ":attached_party", ":i_stack"),
(val_add, ":total_size", ":stack_size"),
(try_end),
. . .