What is the model number of my iBook G4?

Under the Apple menu, select "About This Mac...", then click "More Info..."

this will launch System Profiler. Unfortunately the common model name (e.g. something like "A1054" for an Early 2004 iBook) will not be listed by System Profiler, but other useful and uniquely identifying info will be shown there.

you can then cross reference that info in the handy app called Mactracker. knowing a few pieces of info about your machine, e.g. the processor speed and general model type(e.g. iBook) will usually lead you to the specific model. There's also a unique machine identifier shown by System Profiler (e.g. "Powerbook6,5") which can be searched for in Mactracker to give you the more commonly known model name

Unfortunately, that bottom case is the only place the model number specifically is printed.

If you flip up your keyboard, what is the writing near the serial (it should say something like iBook followed by the screen size, followed by the processor speed, followed by the RAM, followed by the hard drive capacity, followed by the type of optical drive...)?

We can ID your machine from this info.

Look under the keyboard

Try look under the battery