As I might have mentioned elsewhere, it is now technically possible to create true stereo out of a mono soundtrack, if that is the only sound element available for THE BIG COUNTRY. If indeed all we have is the mono elements (preferably the mono stems, music, dialogue and sound effects)...
I also messaged KL (actually MisterLime) about whether the new presentation will be either stereo or mono. If indeed the rumored 70mm stereo print cannot be found, it is now technically possible to create (or, in this case, recreate) true stereo from mono to replicate the original premiere...