The Star Trek TNG films in 4K will have the same 7.1 audio as the 2009 Blu-Ray discs.
Not sure how original that is or not. Once again there is no Stereo 2.0 Dolby or DTS mix.
But i have my 2 Disc DVD releases of the TNG films and my Laserdiscs of Generations, First Contact, and Insurrection for the original audio. Its not HD but what can you do.