I think he does, if you wait some time but I don't remember exactly what. I will try and memorize it the next time I go. I'm really lucky because that school in close to the university I study at!
I remember, when I finally got to play the demo for the first time, Qwark said something along the lines of, "You can always count on the Galactic Rangers! No problem is too big, no problem is too small. Well, maybe some are too small. Say, you've lost your cat and there's an invasion on Kerwan, chances are we'll have to take the invasion. But, other than that, no problem is too small!" I've never heard that on YouTube, but maybe that's because, in all the gameplay vids I've seen, the player doesn't "stop to smell the flowers," so to speak.
He said something entirely different the next time I played, though I do not remember what it was. I think Qwark was bragging about how awesome he is, and said something about how he's "just that good!"
Hmmm, I wonder if there are any other areas in the game with random dialogue that's not the same every time you play? That would certainly make listening to the gameplay chatter during replays more interesting.