Sorry for arriving late to this party. Yes the packaging for the Australian Buck Rogers Blu-ray set indicates 2 channel LPCM stereo, but all the audio is actually 2 channel mono (center channel/subwoofer only when DPL processed). The blu-rays have the broadcast version of the pilot in HD with the mono audio as expected for a television show of that time. It also has a PAL upscale of the theatrical cut, but again with mono audio. The region 1 DVD set has the theatrical cut with mono audio as well.
I recently tracked down a “Discovision” laserdisc to hear the stereo mix. The image on the disc was mostly OK - a bit of white noise dots, but nothing like badly rotted discs that I have encountered long before. The analog, non-CX audio on this disc is like what others here have stated - a lot of crackling noise. The audio is definitely stereo though - typical of a matrix encoded stereo track of that time. I had thought about trying to remove the noise, but this would probably be a huge task. An ebay search turned up a European laserdisc release. I don’t have an LD player that will play PAL laserdiscs. Then there is also the issue that PAL transfers speed up standard 24fps movies by four percent so they play back at PAL’s 25fps with noticeable difference in pitch for the audio and temporal motion for the video. Finally, I don’t know if the PAL disc would fare any better after all these years when it comes to laser rot. I was hoping there was a Japanese LD release (as there was with Mission Galactica - 1987-ish release for the LD) as this would readily play in US NTSC laserdisc players, but I have not found any evidence that Buck Rogers was ever released on Laserdisc in Japan.
I decided to try one other legacy format. I found an old VHS tape (yellow box). The side of the box was only marked “Hi-Fi” - without the word “stereo” which normally would mean that the audio was two channel mono. The cassette itself only had the Dolby “double D” mark; which alone only means that the linear audio tracks have “B-type” noise reduction. However the tape tracked and played back well through an old industrial Hi-Fi VTR and the audio was the same stereo as the Discovision LD. Unless someone can find a laserdisc without rot, this VHS Hi-Fi stereo may be the best audio available for the theatrical cut of Buck Rogers. This was also released on Beta back in the day as well, but those tapes are harder to find and I have never had any Beta decks.