Mr. Purvis,

I recommend you go to the website below and explore around. From what I saw, I think they may have what you are looking for or you can ask the question for their assistance.

Smithsonian National Postal Museum
http://www.postalmuseum.si.edu/

I hope this helps.

Respectfully,

Gerald D. Hodge, Jr.
War Between the States Historian
Historian: 39th Georgia Volunteer Infantry Regiment
http://39thgavolinfrgt.homestead.com/39thHomepage.html