The ebuild currently has LICENSE="as-is" which most likely is wrong.
sparvg2004.conf included in the zipball contains only sparse license information:
DistributionLicense=Copyrighted; Permission to distribute granted to CrossWire
Permission granted to CrossWire doesn't necessarily imply that we're allowed to redistribute the package.
Fixed by adding a sword-sparvg2004 license to the tree and modifying the ebuild to use that one. The license from sparvg2004.conf, found in the About= section, says that organizations who are distributing or printing it for free may do so as long as they don't change anything, so I think we're in the clear there, but if this proves to be a problem in the future we can set RESTRICT="mirror" and that should be sufficient.