If the TCP port is setup correctly that's already very good.
I just realized that part of your uncertainty might come from using the built-in firewall of Mac OS. Frankly, I've never used it, so I don't know how hard it is to open UPD ports. Unfortunately, I can't test it right now, because I have other firewall software running (namely BrickHouse).
If you suspect that your firewall is reducing amule's performance you might wanna try disabling it for a day or so. A Mac is already very secure without a firewall, so this is not a big security risk. Plus, since you are using a router, only the ports you have specified there get forwarded to the Mac anyway, which is in principle the same as what a firewall does.