Yes, there are several awful transfers of this film on the market - that's the problem with PD stuff - but MGM's transfer (which is on this release) is as good as this film is ever likely to look. I'd urge you to check that one out before spending any time on restoring the inferior releases.
BTW, fun as TLMoE is, it certainly is not better than the original novel (whose subtleties have eluded every adaptation to date).
Heck, it's not even as good as The Omega Man... ;-)