How can I tell if I have an older Apple PowerBook G3 or the newer SDRAM version

How can I tell if I have an older Apple PowerBook G3 or the newer SDRAM version?

The main physical appearance difference is in the mouse buttons.

The older Apple PowerBook G3 has a squared off Trackpad with a squared off mouse button that wraps from the top surface over the front edge.

The newer Apple PowerBook G3 that uses SDRAM has a more rounded Trackpad and a banana-shaped mouse button.