Should be a no brainer. You have root. So just fire up what ever flavor of application management your flavor of Linux uses -- yum, druid, slac, apt, ... and take inventory. Is GD installed? Was the package the "development" version (you'll probably want that one) while I run *BSD's. As I recall, getting all the optional libraries often wanted on a Linux box required the development packages. Anyway. If you perform this step ahead of your localized Perl install/upgrade. You shouldn't run into any difficulties that aren't easily handled.
use Perl::Always or die;
my $perl_version = (5.12.5);