Weapon components question

[CyberPlugg]

Can I with my knowledge of C++/C#, 3D MAX.
Make a large-scale mod for weapons?
You will be able to literally replace parts of the other. Like in the Fallout/escape from tarkov games. In the game itself, for example, replace the entire" body " of the weapon and put another. Change weapons bit by bit. The handle, for example.

Will the game itself allow me? Do I need to write any software / plugins?ц