I'd use LWP::Simple's mirror($url, $localfile) in place of the if/else test. That way, if they update it, you'll get the latest version, and if it hasn't changed, it's still minimal traffic. It also automatically avoids creating the local file if the remote fetch failed, so you won't end up with an empty RFC file if something's broken.

-- Randal L. Schwartz, Perl hacker