The DVD expansion bay device that ships with the PowerBook (FireWire) does not work with any previous PowerBook G3 Series model. The previous model DVD module does not work with the PowerBook (FireWire).
Battery
The PowerBook (FireWire) uses a battery similar to the PowerBook G3 Series (Bronze Keyboard). The two batteries are interchangeable between these two computers only.
Other expansion Bay Devices
Expansion bay modules for the PowerBook G3 Series (Bronze keyboard) will function properly in a PowerBook (FireWire). It is possible that some third party expansion bay devices made for the PowerBook (FireWire) will not work with older PowerBook models. You should consult with the third party vendor before purchasing if this is of concern.