According to IMDB, the audio for the original film was 4-track Stereo, just remixed in Dolby for the re-release. (but I'm beginning to think this info is incorrect, I think Walter Murch have said that Apocalypse Now was the first film he worked on in Stereo)

In the original release, John Milner is listed as having been killed by a drunk driver in June of 1964 in the closing segment just before the final credits. When the movie was reedited in 1978, the date of his death was changed to December of 1964, most likely in anticipation of the release of its sequel, More American Graffiti.

The '78 cut should be easy to restore though with the help of Laserdisc footage, the documentary footage is not enough as it don't have the complete opening titles.