Well, the difference is not major, but there indeed is a discernable colour shift in the lighting on the spaceship, especially the one of the Nostromo. But to say that it's incorrect, I will always say is a bit rash. There's simply no way of knowing that. No two transfers of Alien have ever been exactly alike because it depends on the colourist's preference for little tweaks like that, so some shots in older ones match the BD and some are slightly different, but those older transfers varied from each other in equal amounts as well, and the PAL and NTSC versions of the same transfers even disagreed with each other. I am inclined to give them the benefit of the doubt that the Blu Ray is more accurate than the Laserdisc/VHS masters of the past (was the 1999 Saga transfers from the 1996 masters? I thought they might be...). Especially considering the pains they have taken to get the original starfield-less shots and keep the original lighting in the Brett scene, etc., plus they are working from the original negatives and not interpositives and print masters like the older ones. It just seems slightly abritrary to hold up a particular transfer from 1999 and say the film must look exactly like this in every single respect. I'm only going by screencaps, but the BD skin tones by far look the most natural, the lighting and colour just looks "right" compared to older versions; in some ways it seems like it is about halfway between the two older theatrical 1999 and 2003 palettes.
In fact, if you look at the 1999 transfer shots posted above, you can see that there is blue in the lighting, it's just very washed out (the shot of landing craft is more apparent). So, it really just seems like the colours have better vibrancy in that respect. I guess you could argue that the BD has nudged them a bit more than they ought to. But I can guarantee that the earlier transfers were toned down a bit more than they ought to be as well, simply because you were dealing with older, fading IPs and much more limited telecine technology without the ability to even display all the colour information there anyway and again subject to preference and eye of the colourist to fiddle around with things to get them to look the way he thought they should look.