Not a chance—at least not as a primary source. Though the 1997 SE mix of the first movie was mainly derived from an original four-track master, it has so many additions and changes piled on top of it that deleting them all would probably be more trouble than it's worth, and there is no suitable discrete channel source to replace them with.
Worse, a fairly severe level of dynamic range compression was used during the mastering process, supposedly to eliminate 'harshness' in transient peaks, so the broadly powerful sound of the 70mm version has been lost due to this destructive alteration and cannot be recovered.
The SE mixes of the other two movies are completely new and have little resemblance to the way they sounded in 70mm, despite having less changes in content made overall. The 'aural aesthetic' is not the same.
Emulating the 70mm mixes by using the 1993 versions and editing as needed comes much closer to that original sound, despite having to settle for the upmixing of matrixed stereo tracks in place of true discrete channels. The SE's make good sources for the bass, but some parts have to be substantially altered in order to sound like they actually belong there, and others deleted altogether.
At any rate, as I've mentioned before I'm definitely interested in using the LFE channel from the DTS track of the first film for the new version of the recreated 70mm mix, as it may provide improved fidelity over the AC3 laserdisc. As such I eagerly await news of progress. ;)