Looks legit. It has visible matrix code and catalog number. Unofficial/fanmade cd artworks usually don't go that far.
The cat number is CD-C95-861-1
The game (Fallaout 2) had a catalog number CD-C95-861-2
I don't know if this is original edition from 1998 or some later re-edition. Didn't look into it yet. But since since cat number of OST CD is so similar to game CD, I would assume they came out at the same time.
So I think it's possible the Soundtrack CD was included with some editions (or certain copies) of the game.
http://www.rfgeneration.com/cgi-bin/...-016-S-31330-A
http://www.mobygames.com/game/fallou...CoverId,37724/
http://www.rfgeneration.com/cgi-bin/...1330-A&type=gs