Rigging a model won't deform the mesh if you don't want it to, if you're willing to take steps to prevent it (e.g. turning off bend as TG just said).  Making a bunch of separate pieces set up to be children of bones doesn't offer any advantage, it just makes the item a pain to work with for the user.

Turning off bend does have the problem of causing the mesh to break where polygons are adjacent and connected to neighboring groups, and you need to be cautious of children bones causing deformation in their parent, but this isn't a big deal.

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