The hard part is adding RichFaces. However, their instructions are pretty straightforward. The RichFaces tab controls are fairly easy to work with.
On the other hand, to use JSF 1.2 you'd need RichFaces 3. I strongly recommend that you consider moving up to JSF 2.x and using RichFaces 4, since both JSF 1.x and RichFaces 3 are obsolete. And it is a non-trivial task to migrate RichFaces 3 to RichFaces 4 . Might as well endure the pain now instead of being forced to at some inconvenient time later.