Hi!
I don't know if your patron is actually able to go to the Smithsonian Nat'l Museum of Amer. History but in the numismatics department, Dick (Richard) Doty is the definitive expert. I do not have Mr. Doty's direct line to his office but one can call the museum and ask for him. If not then the next person to know something would be Karen Lee and she is a curator in the same department. Also, there are a few volunteers with loads of knowledge on the subject of coins. 

Also this very nice lady sent me her email address ([log in to unmask] and I believe she is a lister also) She is also very knowledgeable in the field of numismatics. She writes for Coin World and she's a conservationist/preservationist so she may also have some connections.
Hope this helps. 

> Date: Tue, 29 Nov 2011 13:54:59 -0500
> From: [log in to unmask]
> Subject: [MUSEUM-L] Need help please
> To: [log in to unmask]
> 
> Afternoon Listers,
> 
> Would anyone out there happen to know (or know someone who knows) about Roman Empire era coins? We have a patron that is looking to have a coin authenticated, and have no idea of where to send him.  
> 
> Thank you in advance!
> 
> Regan Brooks
> Registrar
> Gaston County Museum of Art & History
> PO Box 429
> Dallas, NC 28034-0429
> 704.922.7681 ext. 107
> www.gastoncountymuseum.org
> 
> Become a fan of the Museum!
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> 
> 
> " Be nice to the archivist, or she'll erase you from history!" - Anonymous
> 
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The Museum-L FAQ file is located at http://www.finalchapter.com/museum-l-faq/ . You may obtain detailed information about the listserv commands by sending a one line e-mail message to [log in to unmask] . The body of the message should read "help" (without the quotes).

If you decide to leave Museum-L, please send a one line e-mail message to [log in to unmask] . The body of the message should read "Signoff Museum-L" (without the quotes).