Yeah, basically the mesh files contain not only the main body for the character, but also any weapons that the character uses. I'm told that CA of course designs them separately, but irreversibly links them as part of the mesh-building process to form the meshes that ship with the game. A crew of guys are collaborating as we speak in the Modding Research Wiki forum to crack the .MESH file format, and one application of that will be the ability to modify weapons and shields w/ widely available model editing software.