I knew we could count on ufolev to test this further, but I have to agree that it doesn't look as though the MLAA is working, at least from the screenshots.
I think that ufolev may have got the screenshots by using the in-game screenshot facility that can be enabled from a small menu hack. In which case, it is very unlikely that any postprocessing effects would be grabbed.
I find these third-party postprocessing programs quite interesting, there is one out there which enables all sorts of effects in many modern games (not just one), but can't think what it's called. There's also one specifically for the Dark Engine games such as Thief 1 & 2 and System Shock 2, which is more along the lines of this as those games are from the same era. But unfortunately, most of these kind of programs are graphic card-specific, and at that, driver-specific, and even then may not work for everyone depending if they 'hook' it into the game successfully or not.