Are you referring to that Free Beer And Chicken album, if so which one please? Some releases say they are actually Quad, but I've only heard the CD (still need to check it out more).I'm playing a reissue LP (S-75900 in runout) through an SM2 and get very little from the rears, mostly just the lead guitar in rear. Everything else is in the front.
Don't have and original LP.
I listened on headphones and it sounded like it could decode well