Still not sure I believe that the letter is genuine.
I found a "real" e-mail address on the USC website and sent a quick note. (firstname.lastname@example.org) I'll see what happens.
Libertarian founding father - John Hospers -
is listed in the Los Angeles phone directory.
This is an automatically generated Delivery Status Notification.
Delivery to the following recipients failed.
FWIW...I contacted Dr. John Ray (this letter is on one of his blog sites too) and he said he receieved the letter directly from Dr. John Hospers in an e-mail. He claims he is certain it is genuine.