You need to remove the grills and look at the surrounds or edges of all the round speakers for rot or they even could be missing. If so, all the speakers need to be "re-foamed" in order to be used. If you don’t want to tackle that, they would be part units and not worth much. Also for these to work correctly, they need the equalizer that came with them when new.
https://i.pinimg.com/originals/62/76/54/627654b9607299936dbdc7d75c91f797.jpg
https://img.usaudiomart.com/uploads/large/1088800-a7656ea1-bose-series-1-901-speakers-with-equalizer...
https://i.pinimg.com/originals/62/76/54/627654b9607299936dbdc7d75c91f797.jpg
https://img.usaudiomart.com/uploads/large/1088800-a7656ea1-bose-series-1-901-speakers-with-equalizer...