Yes, this is for RHEL/CentOS 7 specifically.
It didn’t seem like the iptables commands were actually needed for the image of CentOS 7 I was using, but that might not always be the case. The firewall-cmd’s are definitely needed.
This command is needed for CentOS/RHEL 7 clients as well:
firewall-cmd --zone=public --add-port=52311/udp --permanent