It is a real shame that somebody was able to pick the true plums out of the collection for so cheap. I wish I had realized that they were actually on sale somewhere.
David B, I strongly recommend that you pull out whatever Model Fs you still have left and set them aside. They are "the good stuff".
I don't know why some people get excited about the 1390120s, they are less desirable than Model Ms with LEDs, except maybe as parts donors, in my opinion. But then, after using Model Fs for a couple of years, I have become mostly indifferent to Model Ms anyway.