I have a macbook 2.16ghz that i bought in june of '07. Unfortunately, i am out of warranty, and my top case (keyboard area) is cracking where the spacers meet the keyboard. I'm looking to replace the top case with possibly a black one (only because it would look cool), however I can only find the new versions (with the different set of f-keys). Are these new and old versions of keyboard interchangeable? or do i need to buy one that was made specifically for my model? Thanks!