i myself rather dont know
It looks, that model has 2 or more bodies opticaly as one with different textures layers, you can see it in my zip, where you reckognized unity. I observed some kind dynamic change of appearing of others textures, when ship is damaged or wheathered, but diffuse (main) textures are somehow ripped for individual bodies. Fortunately, most of texture is on one body and small part on second, so there just must be defined which is right for our purposes (i did it visualy in game).
For example starting corvette has 3 bodies covered in one, tennhausen has 2 bodies, ...
i was still unable made progress with unity, so i used old program 3d ripper, but this works on 32 bits only.
extract from ripper (many objects captured) import into 3dmax8, here is important define body, which we need, rest can be deleted (practice). then i exported as obj (as imd was not working) and open imported in blender. we can see dual or triple body. can be used some trick for reckognize these parts in game environment. For example dual is set as paralel bodies, one part is changed(size), then export as obj. Imdeditor convert it into imd + set adequate texture. in game we can decide, which part is "right" and in editor (3dmax or blender) we can delete other, then resizing, setting orientation adequate for x,y,z axis, etc...
For start I did small test with ripper in SOSE, there is just few objects from start of game and we can give command for destroying itself.
I believe, that right learning for unity can speed up whole process.
For first aproach could be enough, i am still in first stage of it.
There is test for SOSE
https://ulozto.cz/!8wuaezldelLc/cargo-jpg