Hi Al, if there was any sonic difference between having the preamp right-side-up and upside-down, I was never aware of it. (As best I remember, I tried listening for such when I first turned it over, but not with the expectation of hearing much if anything different.) I did, however, eventually change the power cord again, from the model I had chosen over the stock cord at the time I reinstalled it right-side-up, to another model I use today throughout my system, and those comparisons were carried out in normal orientation using the adapter. (I should note that some other aspects of my system had also changed during that time span, and still more since.)
As a postscript, I also remember talking again to the ML dealer and mentioning my findings. I thought I was enlightening him, based on what he'd told me, but his reaction was that he wasn't surprised, that of course if you upgrade the power cord on any component you're likely to hear some improvement in a revealing system no matter how good that component's power supply, but getting into that just wasn't practical for his ML preamp customers. (I'd also note that the No.38x series was designed prior to the time when aftermarket power cords came on the scene, and I do believe that ML's later preamp offerings dropped the obscure receptacle placement.)
PPS - Hi Richard, almost as soon as I'd posted I wished I hadn't taken the bait, so thanks!
