Now which you mention it, the primary 2 tracks seem to lack reduced bass, (aside from a bass drum strike just ahead of the fade away from Custard Pie). But then “In My Time of Dying” appears to have some additional bass… unsure what was happening here, most likely https://ledzeppelinplatinumrecord19652.blogginaway.com/27247227/the-definitive-guide-to-led-zeppelin-gold-records