does the powerbook g4 have a hitachi hard drive

Check on ifixit for repair and parts information. https://www.ifixit.com/Guide/PowerBook+G4+Aluminum+12-Inch+1-1.5+GHz+Hard+Drive+ Replacement/548 If this is your computer the pick shows a Toshiba drive. I did not read the article so do not know if the pic is just a generic image or if it is specific to your computer. But it matters little since any drive with the correct size and connections will work.

The original hard drive in a G4 powerbook was Toshiba not Hitachi.

But really the brand is not really important.