Right you are: The Internet Movie Database lists an original score by
Jerry Goldsmith for this movie, as well as "Non-original music" (!) by
Hanson (Symphony No. 2) and Mozart (<Eine kleine Nachtmusik>). See
http://us.imdb.com/title/tt0078748/combined. I sure don't remember
hearing either when I saw the movie over 2 decades ago, but I have no
desire to see it again. Bet the Hanson is only in the closing credits.
Anyone else care to check it out?
Incidentally, <Alien> is the only movie in IMDB's exhaustive database
on which it credits music by Hanson.
Nick Jones
Atlanta, Ga., USA