Muffy's authoritative copy of Brotherhood arrived yesterday, for purposes of the great listening experiment. So far I have performed careful track-by-track comparisons of the first two tracks, comparing the Muffman's pristine Factory CD version with my own humble Qwest copy. So far I am not detecting differences. Of course the listening experiment will continue, and I will provide further reports.
Based on multiple comparative listens to the first two tracks, I continue to think that whatever sounds "different" about Brotherhood has mainly to do with the treatment of the vocals.