> And, secondly, why is it GNU-GPL-v[23], the "GNU-" bit is
  > unnecessary. Or maybe we should call the BSD ones

It's necessary and correct.  GPL stands for General Public License.  The
FSF includes GNU when describing it; see the title on
http://www.gnu.org/copyleft/gpl.html.

  Shouldn't copies of all licenses be in pkgsrc/licenses?

Yes.

And I think we aren't yet adding uncommented LICENSE= tags to packages
for free licenses.