Dear Mr. Cleary,
Thank you for posting your request on History Hub!
The National Archives as the repository for the permanently valuable non-current records of the Federal Government does not have access to any information regarding historical documents in private hands. The Antiquarian Booksellers Association of America maintains a list of their members who may be able to advise you regarding this topic at ABAA Booksellers.. You also may wish to contact auction houses such as Sotheby's and Christie's.
We hope this is helpful. Best of luck with your research!