Some are. But there is no DVD or other source for a 5.1 remix of the entire Peter Gabriel 3 album that I know of. Do you? But he's got every track listed as a '5.1 mix'.
He's also got a well-known 1978 KBFH (definitely
not quad) FM radio broadcast Yes concert that he's calling a '5.1 mix' that , according to *his own information* on his Youtube page, cannot possibly be. Here's
his lineage info for it (with my note in italics):
YES
The Forum
Inglewood, CA.
October 5th 1978
90 Min K.B.F.H. Special
KISW FM Broadcast Aired November 26th 1978
<---100% not a quad broadcast!
Reel to Reel Master @ 3 AND 3/4 ips
From The JEMS Archive
Transferred and Presented By Krw_co
Here's what you find in a
torrent for this source (boldface mine):
Nothing surround-y about that. Plus the torrent's got more info about when/how the 'Reel to Reel Master' was recorded and by whom
When I first made a case for the extreme unlikelihood of his audio being a true 5.1 remix, (and noted the incorrect date/venue data he copied from the torrent), he was most unhappy:
I then added the trading page evidence above; so far he hasn't removed it