Hi, Denis:
As you know, I've been trying (without any success) to find any tangible evidence of a HSCA /UPI transfer memo or receipt for the return of the original Nix film to UPI. All I've got is anecdotal evidence (albeit from a number of people) that such a memo / receipt exists. Find a document, and we'll know where the camera-original film is !!! Happy hunting, my friend, and good luck in your endeavours.
Chris