Theatrical DTS is a completely different format from home video versions, both in the compression algorithm used and the way the audio data is actually stored. There is no 'core' track to be found.

There is also not actually a discrete LFE channel in the theatrical format, either; the low frequency information is stored in the surround channels and then low-pass filtered out at 80 hz. This was due to there being no provision made for channels of less than full frequency range (compared to Dolby Digital which from the start has used a channel of limited range up to 120 hz for the LFE), and insufficient bandwidth to add a sixth full range channel. The home versions of DTS operate more similarly to Dolby's model in this regard.

Those old SE bootlegs do not contain true DTS tracks, from what I recall hearing. They are simply the AC3 laserdisc mixes converted to the DTS codec in order to have the name recognition, but there is no actual benefit to them.