OK, got something both interesting and also probably very technical to ask of any modellers who happen to be reading...
In brief I spent the afternoon cramming how to import/export psk using 3ds and actorx. I checked my model and exported it using the 2 distinct skin texture assignments. Proof it worked:
► Show Spoiler
Unreal skeletal exporter for 3DS MAX - Model information for [MYMODEL.psk]
Skin faces: 16862
Skin vertices: 19005
Skin wedges (vertices with unique U,V): 15465
Total bone-to-vertex linkups: 25296
Reference bones: 113
Unique materials: 2
= materials =
* Index: [ 0] name: material_0
Original bitmap: Texture1.tga Path: C:\DELETED
- Skin Index: 0
- render mode flags:
* Index: [ 1] name: material_1
Original bitmap: Texture2.tga Path: C:\DELETED
- Skin Index: 0
- render mode flags:
(Here it lists the bones, all are good)
I then checked the psk file with UModel and it looks good, both textures are assigned. So then I coded my UScript import and checked the actor in editor: back to single texture (the first one) applied across the entire model.
I even tried to manually assign the texture in the script like this:
#Exec MESHMAP SETTEXTURE MESHMAP=MYMODEL NUM=1 TEXTURE=Texture2
It compiles again, no error thrown on the NUM value as being out of bounds but still the actor has a single skin that ignores the second one. BTW, if I manually place the second skin using multiskin in ed the gun texture is correct so it's somehow combining both into a single NUM assignment on import.
Could someone please spitball me some "It could be this" things? I promise you that I'll make a set of video tuts for all this once I'm proficient so no one else has to piecemeal it together again like I've had to do. I've followed everything I can find on this and nothing seems to work. Like everything UDev it's going to be something either simple I'm not doing or it's a bug in the export code.