I believe you have a Unibody laptop. The "unibody" mean the palmrest area (including keyboard) is part of the main frame where as on the earlier non-unibody models, the Top Case (aka palmrest) area was separate from the base/main frame (plus the keyboard was removable on the earlier non-unibody models). The non-unibody models were very similar in style to the older PPC PowerBook G4s.
I guess you could take the bottom case off to check the physical dimensions of the two optical drives, but keep in mind how far back the MBPro optical drive sits from the edge of the case....I'm guessing it will have a bigger gap than the one in the MacBook. I beleive the bottom of the two drives will measure the same. From what I recall the MBPro optical drive has a metal extension on the top plate of the optical drive...and no, swapping jhust the top plate of the optical drive won't work here due to the grapping/ejecting mechanism of the drive won't be able to negotiate the difference in placement. Otherwise the two optical drives would be likely be interchangeable (assuming the MacBook is using a SATA based optical drive).