It is possible to import a set of RCS (the file format CVS uses to store history) files at Savannah. RCS files usually end with a ,v extension.
Just open a support request at https://savannah.gnu.org/support/?group=administration with a URL for a tarball containing your CVS repository. If you do not have a URL, you can either attach a tarball directly to the tracker if it is small, or note in the request that you do not have a URL and a Savannah hacker will ask you to send a tarball by mail.
This is the procedure for importing an existing CVS repository, not a set of files. Be sure to send the RCS (,v) files, not a tarball of your latest release. To simply import your latest release, use the cvs import command.