Not necessarily. The only licensing requirements to put a module on the CPAN is that you choose a license and allow sufficient distribution rights that it can be distributed. Not all modules have licenses, but the CPAN testers utility looks for that situation and alerts the author appropriately.

Granted, many are available "under the same terms as Perl", but some are not -- some are BSD only, GPL only, and Artistic only. Some are even public domain. You have to read the licensing section of the POD (which should be there for any module on the CPAN) to make sure.

If it's not there, politely suggest to the author to make it available.