Well I finally got off my b*tt and spun my unremastered Zep IV. The harmonica is panned right on my copy, too. (I don't have the remastered Zep on CD. Yet!) Made in USA by JVC / A2-19129 (front of disc beneath the Atlantic logo) / 19129-2-v8e13 (inner circle). Back cover: A2-19129 Made in USA. A2-19129 is also on the spine. Then, getting to my feet, I went downstairs and spun the Classic Records vinyl. Harminoca is panned left. I'd guess the 'goof' was on the original CDs. Someone was not paying attention somewhere.