Yes, but you may have to punch holes in the firewall _as well_. I don't think selinux security context would override any local firewall rules which (as they stand today) lock down all ports that aren't explicitly enabled for a service.
Thats why you should be using selinux to prevent unwanted port bindings system wide. Disable firewalling in this case. Or at least limit it to ports <1024 or something.
There's still the annoying question of ports the *kernel itself* is listening to. NFS serving likes to do this, and use random ports just above 1024 to do it. ;P