The bells are in the north and south towers. The fire hoses were pretty focused on those, because they are filled with the same maze of timber steps and supports as the roof/attic was. I've been up in the bell towers to take photos with the bells, as I'm sure many people here have. Dizzying maze of wood.

If that wood had caught fire and the bells had fallen, the towers would be gone, I would assume.

So to answer your question, I'm sure the bells survived, otherwise we would know it.