Haven't scrapped one myself, but I would think besides what you mentioned, that you should also have a small fan (electric motor) for cooling the unit. They usually run pretty hot from the projector lamps. There might be some brass gearing depending on how it's feeding the microfiche. Possibly an aluminum heat sink(s).

If you end up tearing it apart, why not take some pics for a post? Also, check and see if you can get more selling it for parts. You never know.