here is a tip in order to make 100% sure it's syncs, since the mono on the 35th anniversary edition is a 5.1 mixdown (why even bother to include a mono mix, if it isn't the real deal?)

1. if possible retain the video from the laserdisc. properly inverse telecine it
2. add pcm audio from the ld to the ld video - sync it with the captured lossy audio, unless you captured the pcm right away with the pcm track
3. add ld audio & video on top of the to be synced movie
4: now sync using the actual frames and not waveforms

why is the method better? because you an actual a/v feedback if your work is sync or not.

alternatively if you don't have the ld video you can sync the audio to the 1999 dvd, which contains the actual mono track. from there you move on to the bd.