I use blender, I looked at my own 3d model to see if some vertices where not assigned to bones and I concluded they were all assigned to the bone closest to them. When I highlight bones in edit mode, the vertices assigned to them will light up and I will be told how many vertices out of the maximum are assigned to the selected bone. When I selected all the bones it was exactly 5224 out of 5224 vertices. So I would have to say that each vertice is assigned to a bone.