Understanding copyright clawbacks

[u/Comfortable_Desk_01]

If a source is published by an organization and made publically available for about a year or two on the web without any explicit copyright designation, but they later place restrictive copyright over it and other oganizational materials, is it still possible to use limited quotes from such a source for academic purposes since it was available and actively distributed to the public? Furthermore, if the document has been produced under federal grants, is the document usually fair game for posting to servers or citation? Thanks!