Interesting note about my 2300c is that it has a trackball instead of a trackpad. It was like this when I purchased it, so I'm not sure of the history, whether the wristrest or trackpad broke and the wristrest with a trackball from an older Duo was cheaper... maybe a previous owner just preferred the trackball and swapped it out. Who knows...
Most likely an upgraded previous model. Apple never really wanted to release the PowerDuo, but they'd promised all Duo owners a PPC upgrade path. I've got a lot of Duo parts, some of the, presumably, upgrade decks have something funny about them. IIRC it was the missing nameplate or some such.
One of my favorite PowerDuos has the same
TrackBall UPGRADE, pointing devices were/are
meant to be spherically correct!
The 2300c's Active Matrix is a full 640 x 480, whereas all the others, AFAIK, were 640 x 400. The PowerDuo set at 16 bit Color will letterbox its display at 640 x 400 . . .
. . . coincidentally, at that resolution and pixel depth, the image perfectly fills the bezel opening of the PB100! }
That's where I keep one of my 2300c LCDs. I originally intended to do a "reverse digital picture frame" hack using the first, and best, of the 100 series PBs by converting it from B&W into a 16 bit SlideShow/Display, but that toybox has been sitting untouched for a
very long time . . .
. . . I'm still ruminating re: the possibilities . . .

)