Depends what your adding. If your doing steampunk your probably gonna add noticebale weight since they tend to like all sorts of metal gagets and gears added. If your just ading a little bit if stuff, no sound diff. If you cover the bass with all kinds of metal gagets, then you can expect to hurt the sound of wood since it would become a laregly metal bass body.
Life for its own carnal pleasure sake. Bass Guitar: Jackson JS3. Rotosound swing66 strings. Zoom club#2. Bass synths: Maudio Venom, & Novation KS4.