Is there any mod that changes the default skin in the game ?

Perhaps the Skins plugin? There's also the Item Skin Randomizer. You'll need to be a bit more specific though, as "the default skin" could mean many things.

For example if you are from russia you do default t-shirt in-game to be russian one and change the skid so people when craft the default skin have russian tshirt crafted instead... I  think he wants this.

Hi,
I mean craftable skin in the game. For example, when I find in the box thompson rifle to have another skin, or any other outfit.

Merged post

Does anyone know the answer?