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.