Ok.. I'm still confised. Please clarify a few things. What do you mean by:
Gun interface (weapon menu? weapons that soldiers hold? health/ammo/jet bars?)
ModLauncher (default start.exe or some other program?)
"same CSCS gun interface not the CS mod by SK's gun sounds" <--- does that mean that some things from the mod work and some don't?
Either way, your mods should be like:
Soldat/Mods/CSSC Official Mod/gostek-gfx
Soldat/Mods/CSSC Official Mod/interface-gfx
Soldat/Mods/CSSC Official Mod/weapons-gfx
Soldat/Mods/CSSC Official Mod/sfx
And so on. I had no problem with CSSC.
Check if CS mod by SK has similar folders, like this:
Soldat/Mods/CS mod by SK/gostek-gfx
Soldat/Mods/CS mod by SK/interface-gfx
Soldat/Mods/CS mod by SK/weapons-gfx
Soldat/Mods/CS mod by SK/sfx
etc.