They are the same. For some reasons, subdirectories created in @INC while installing modules are default executable. Can I change this? It's annoying to have to go chmod every directory manually.
This is getting slightly un-Perly, but have a look at umask to set default access rights on newly created directories and files. You should find it in your friendly neighbourhood manpages.
Of course, Perl being what it is, it provides a umask function. Check out the documentation.