I'm not sure, but I'd assume so. You could have a look through /opt/zimbra/bin/zmschedulebackup.
In any case zmschedulebackup currently has an important limitation in that it can't set the --noZip option.
Bug 45634 - add noZip option to zmschedulebackup
So, for many of us,
crontab -u zimbra -e is necessary & how we do it. Just do be aware that your changes may be overwritten on upgrade.