Alien's got a very saturated color palette, I think, much unlike either the BD or the D-Theater, which has the color palette of the 2003 Director's Cut reissue.

If you look on the original Halloween II BD, at the Terror in the Aisles documentary, there are clips from Alien which look very, very colorful. As the documentary was only made a few years after the original release of Alien and appears to use footage from a timed 35mm print, it could be an accuate color source. The most accurate release, to these clips, is the 1999 DVD. My two cents.