Item Mods - Modding Inventory items

I originally asked about modding items in this post, but have since learned how so I thought I would edit the post and share what I have learned:


First lets look at the directories for the files involved in modding the inventory case items:

MODELS
The models in the inventory case that we can move around/discard are located in: \BIO4\SS\eng\ss_pzzl.dat
The models in the inventory case that we can examine (the ones rotating) are located in: \BIO4\SS\item
The models in the inventory case for Mercs that we can move around/discard are located in: \BIO4\SS\eng\omk_pzzl.dat
Another model that is used is the model found in:\BIO4\SS\cmn (I think this is for enemy drops)

The models that we see throughout the game in the rooms are located in the ITM files inside the room UDAS files (the ones we see flashing with the white highlight). These models/textures are also used by the game when previewing these items before picking them up (when the model is displayed full screen when we pick it up and the game asks us if we want to take/use the spray).

SPECIAL NOTE: ABOUT SS.PZZL
If we are dealing with the ss_pzzl.dat file we just remember this: 

"The original size of the pzzle.dat.lfs is only 235kb, but when you use the .dat tools to open the the archive the file size changes to 1333kb, just under the limit which is 1339kb. The size limitation refers to the final repacked SS_pzzl.DAT file, not any of the files within as far as I know. Since we cannot recompress the DAT file with a LFS extension we are stuck with this limitation. So just to be clear here… The limiatation is on the final ss_pzzl.dat file which is 1339kb" (as described by the master modder LeagalSoul)
Some workarounds for the file size issue are discussed in THIS post
(EDIT - this size limitation of inventory models is no longer an issue if we are using Razor's DLL)
 
BIN LIST
I have compiled a RE4UHD Ultimate Item BIN file list for people to use.

TEXTURE LIST
The various texture pack files in \BIO4\ImagepackHD\ are as follows:

22000000 -22000097: Inventory items (used by models in: BIO4\SS\CMN) example itm0e.bin
43000000- 4300009f: Examine Items (used by models in: \BIO4\SS\item) example idm037.bin
3b000001: ss_pzzl models. (used by models located in \BIO4\SS\eng\ss_pzzl.dat) example: ss_pzzl_002.bin

The numbers of the model files directly relate to the files in the ImagePack & ImagePackHD folders, particularly those in the 43000000 range. Example is that the file 43000037.pack.yz2 is the texture file for the Handcannon, which is idm037.BIN file

The game orders the texture files in this format:
001-009 00a-00f then 010-019 01a-01f and so on (texture files are in hexidecmal order)
If you see packs of 6 files repeating the same textures, they are mostly language dependent. For example files ending in 01 corresponds to English and 00 corresponds to Japanese

Supportive Material
Also be sure to download the Inventory Cash Fix by the master modder 3getu841 .
Much credit to LegalSoul who helped me understand all of this.