I'm not aware of any new transfer, and I can't imagine they would muck with the aspect ratio.
Rattle and Hum was one of Paramount's first blu-ray titles. Paramount later signed an exclusivity deal with the HD-DVD consortium and the blu-ray was out of print for a number of months. R&H was "rereleased" on blu-ray when HD-DVD went tits up, but it was exactly the same transfer, packaging, extras, etc. That may be why Amazon lists two different releases.
Incidentally, being an older transfer, R&H is actually MPEG-2 HD while most new blu-rays are now compressed with H.264 MPEG-4.