Also, the mono versions of Empire and Jedi were likely downmixes of the stereo tracks (possibly the L, R, & C channels or the full matrixed stereo). By 1980 there wasn’t much point
While I agree that would make sense, in these cases (and Raiders as well), they were indeed different. The same kinds of variations we see between original SW mixes pop up in these as well (different ADR takes, on-set audio instead of ADR, different sound effects, etc.)