Your Mac OS X installation disc should cover the hardware for your Mac. As a matter of fact, most every Mac OS X release should cover the hardware support for the Macs that can run it. Your PBG4 should be able to run Tiger just fine with all the hardware supported, and the same should be with Leopard if your PowerBook is at least 867 MHz.
If you want to know what hardware you have inside your PowerBook, then open the System Profiler by going to the Apple menu at the top left, selecting "About This Mac", and then clicking on the "More Info" button.