I haven't had a real chance to evaluate the Zep I Remaster, but the OP got me curious so I just listened to BIGLY on three different issues:
The original Diament mastering
The 1990 Page / Marino remasters from the crop circle box (the Definitive Box is also a reissue of the Page / Marino transfers, IIRC)
Recent remaster
All of them have the acoustic guitar playing the arpeggiated lines in the right channel. But I've read elsewhere that certain pressings of the older discs had the channels switched for some reason, in particular the Sidore mastering of Zep IV, which I do have.