Well, today Mr. Morrow's goddaughter came into the shop and bought said First Edition!
Carole Landrum was out for a jog, and was quite tickled to spot Black Man in the White House in our window. She tells me that her godfather invited her parents to Eisenhower's Inaugural Ball. She also mentioned that she now regrets having disposed of her parents' books -- there was a copy of this very book among them, of course. But now she has her very own First Edition once again!
(I hope I'm getting all the details right! Ms. Landrum, please feel free to call or email and correct me if I've got anything wrong!)
Thanks to Ms. Landrum for being a good sport about taking her photo, and for telling me the story of why she was interested in this book!