Let's say we are the communist SAG group for this example.
We find we have original George Washington letters that within years could fetch numerous millions.
Do we:
A# Be gracious and donate them all to the Presidential library at no financial gain for the benefit of the nation?
OR
B# Pull a Mrs. Martin Luther King and attempt to gain personal wealth for the family or organization, and to then suck funds from for personal gain, even though you come off looking like a low class creep?
SAG is IMO much closer to answer B.
Although I have no way of knowing, it itsn't entirely impossible that their bylaws require them to maintain ownership over their own archives. By that still wouldn't prevent them from working out a long-term loan of the material to the RWR library.
Let's face it, both you and I agree that SAG is most likely to do something malicious.