litemakr said:

Is this the re-release trailer? If so then it is a valid color reference because it would have been created from a timed print. It would be a couple generations removed from the inter-negative, but still not far off from a release print. There could be a shift towards warmer or cooler, but the trailer itself would not be re-timed shot by shot.

The bigger issue is how the trailer was transferred to video and what could have been done digitally to alter the color, gamma, etc.

Something else to keep in mind is that films were not heavily changed during color timing in the pre-digital days. They didn't have the ability to tweak color like they do today. The goal was usually accurate fleshtones and colors and consistent brightness and gamma. The look of a film was created in camera using filters and lighting, not in post production.

I never said it wasn't a valid reference, just that it shows only a few scenes from the film, so it is not of much practical use. Without being able to see what the colours for the rest of the film looks like in different locations with that specific colour scheme, I think there isn't much point trying to regrade a whole film based on a trailer, many scenes could be ratically different from the blu-ray like the bar scene does and the change in colour will almost certainly not be uniform across the whole film.

As for how it looked theatrically, i've seen shots posted here from 35mm prints of Raiders of the Lost Ark that have the scenes in the desert looking very warm, as you would expect, with natural looking fleshtones taking into account the lighting of the scene and how fleshtones looked on film as that time, not bluish and cold like they are in the trailer. I see no point worrying about how the trailer looks when its just a tiny section of the film so cannot help in regrading the whole film and its colour reliability is questionable due to it being just a trailer and not the finished product.