It was a 70mm print intended for sneak previews and, because the edit hadn't been locked at that point, it would inevitably not have reached the stage of final colour grading.

The same workprint is included as a bonus in the BD set for nostalgia/completion/research purposes, either from the same 70mm print(s) that were accidentally screened in 1990 or from a 35mm reduction. It seems highly unlikely that this unfinished version would have been completely retimed to a 'final' colour scheme for the BD while the actual theatrical version included was demonstrably not.