For what Ingredient explained, seems as though it's the only way to do so. For what I believe, with my knowledge of 3D 'object' animating, the .skeleton is a compressed 3D Blender file which contains all of what the model does in game, like just the actually inside skeleton. 'Connected pillars/bones that perform the animation'(just as you said, armature). However, I presume it can only be opened in a certain earlier version of Blender. I cannot be precise about that since I've only heard slight twaddle about version 2.4 - perhaps that'd be it, but I do not like to exceed a conflict about misleading information. If you like to do it correctly with the actual model in-game, I THINK you have to open the .mesh file with it. Ex: cbody1.mesh (which is packed over the skeleton) + cbody.skeleton.
Correct me if I'm wrong, but I try my best. Hope it helps.