I didn't know that "prodigal Son" was in mono in the official release.
According to this site:[
www.rollingstonesnet.com]
"The released album take of Prodigal Son can be found in Stereo on unauthorized recordings such as "R.S.V.P. Revisited" or "R.S.V.P. New Version".
If someone could post this version, it would be kind
Christian