Quite a number of sources state unequivocably that the Post Office
holds the copyright for all stamps issued after January 1, 1978, and
that -- prior to this date -- stamps are in the public domain.
For instance, have a look here:
...U.S. postage stamps...While not technically public domain after
1978 (all stamps before that are in the public domain) the USPS has a
liberal licensing policy regarding stamps....
All US postage stamps and other postage items that were released
before 1978 are in the public domain...
Numerous other sites make the same claim.
I find sites like Wikipedia and Answers.com to generally be quite
reliable in terms of the information presented, and the passage of a
law specifically granting copyright to the USPS certainly suggests
that they were copyright-free prior to that time.
However, there is no clear-cut confirmation of this that I could find
from the USPS itself. The closest they come is this:
The United States Postal Service (USPS) owns the copyright to all
stamps issued after 1977...
The same link also has licensing instructions for using post-1978
stamp images where the copyright is clearly held by the Postal
In particular, see the links at this page for:
--Non-Commercial Stamp Use Application
-- Commercial Stamp Use page
You can email the USPS directly using the "Contact Us" form provided here:
and can certainly ask them for clarification regarding copyright status.
I trust this is the information you were seeking. Before rating this
answer, please let me know if there is anything else I can do for you.
Just post a Request for Clarification, and I'm at your service.
search strategy -- Google search on [ stamps USPS "public domain" ]
and similar searches at the USPS.com site itself.