All VERY interesting points. However, there are probably some things worth noting. First, it's very difficult to judge what damage was done on screen and what was done afterwards. This was, in fact, a stunt piece that was thrown against a wall and a character fell on it. I can match the main split that happened in the episode to the seam lines on my piece, but as far as the gouges and scratches are concerned, it's anybody's guess.
Second, it IS pretty rare as far as I know. Though they may have made a bunch for the show, I've only seen ONE other at auction. It was at the Christies Star Trek auction and that one was repainted as some funky alien monitor. And according to Christies, THAT was the only remaining TNG-era desktop monitor in existence:
Quote from Christies catalogue:
"One prop computer with nonfunctional backlit screen and swivel base - 10x10 in. - this prop was originally painted black and used in the Enterprise-D sets in Star Trek: The Next Generation, it was later repainted and reused for use on a variety of alien ship sets in Star Trek: The Next Generation and Star Trek Voyager. This is the only known surviving Enterprise-D desktop computermonitor prop. In its original form, it was highly-recognizable (sic) part of the look of Star Trek: The Next Generation."
Now, I know this isn't entirely true because I know of another hero TNG monitor owned by a private collector, but regardless, you don't see these every day. I think most of them were repainted and used in future Star Trek series's. Even the IAW guy told me it was extremely rare after I bought it, and those guys don't ever divulge anything.
Just some food for thought.