I've tried to extract above mentioned (E0_SetMeshPrisoner_LD.upk) package from original game folder and got following warning:
Loading SkeletalMesh3 CH_Ni_Nilin_prison from package E0_SetMeshPrisoner_LD.upk
WARNING: BoolProperty "FSkeletalMeshLODInfo::bDisableCompression" was not found
Loading package: Startup.upk Ver: 832/21 Engine: 8623 Names: 624 Exports: 485 Imports: 85 Game: 8038
check for CH_Nilin_Prison_Body in E0_SetMeshPrisoner_LD
check for CH_Nilin_Prison_Body in Startup
WARNING: Import(CH_Ni_Nilin.CH_Nilin_Prison_Body) was not found
check for MT_Ni_Nilin_Head_Ingame_prison in E0_SetMeshPrisoner_LD
check for MT_Ni_Nilin_Head_Ingame_prison in Startup
WARNING: Import(CH_Ni_Nilin.MT_Ni_Nilin_Head_Ingame_prison) was not found
check for MT_Ni_Nilin_Eyelashes in E0_SetMeshPrisoner_LD
check for MT_Ni_Nilin_Eyelashes in Startup
WARNING: Import(CH_Ni_Nilin.MT_Ni_Nilin_Eyelashes) was not found
check for CH_Ni_Nilin_Hair_ingame in E0_SetMeshPrisoner_LD
check for CH_Ni_Nilin_Hair_ingame in Startup
WARNING: Import(CH_Ni_Nilin.CH_Ni_Nilin_Hair_ingame) was not found
WARNING: SkeletalMesh CH_Ni_Nilin_prison uses vertex colors
Loading SkeletalMeshSocket SkeletalMeshSocket_0 from package E0_SetMeshPrisoner_LD.upk
Loaded in 1.9 sec, 1211 allocs, 0.72 MBytes serialized in 136 calls.
Exporting objects ...
Exporting SkeletalMesh3 CH_Ni_Nilin_prison to E:\temp/E0_SetMeshPrisoner_LD/SkeletalMesh3
And again UEViewer created only SkeletalMesh3 folder, without any textures.