To document how I ended up setting this:
The following command will cause the filebeat and metricbeat agents to start automatically
[root@servername init.d]# chkconfig --add metricbeat
[root@servername init.d]# chkconfig --add filebeat
And shows that they are now set to start at level 2
[root@servername init.d]# chkconfig --list filebeat
filebeat 0:off 1:off 2:on 3:on 4:on 5:on 6:off
[root@servername init.d]# chkconfig --list metricbeat
metricbeat 0:off 1:off 2:on 3:on 4:on 5:on 6:off
The following command sets the runlevel to level 3 for both
[root@servername init.d]# chkconfig --level 2 filebeat off
[root@servername init.d]# chkconfig --list filebeat
filebeat 0:off 1:off 2:off 3:on 4:on 5:on 6:off
[root@servername init.d]# chkconfig --level 2 metricbeat off
[root@servername init.d]# chkconfig --list metricbeat
metricbeat 0:off 1:off 2:off 3:on 4:on 5:on 6:off