Hi @DavidLaw,
Yes, it will work.
Just one thing, you should add --quiet to renew command or you could receive a mail every time the cron job runs. Using --quiet you will receive a mail only if the renew has failed or if it has renewed your certs.
Also, it is a good idea to add the --post-hook parameter to reload apache so the new installed cert will be read and used by apache once the cert has been renewed (this parameter is executed only when a certificate has been renewed).
47 05,17 * * * /root/certbot-auto renew --quiet --post-hook "service httpd reload"
Cheers,
sahsanu