I believe the keyboard is part of the top case on the pre-unibody mbp. You will probably have to remove each individual key if you are just looking for the correct keys. However of the keyboard itself has something wrong with it this may not work.
Im not saying I know 100%, but when I worked as a technician I recall having to replace the whole top case (including trackpad) for a faulty keyboard. Someone correct me if I'm wrong.