Yeah that is standard OP for OpenVPN as far as I can tell. The 1194 (or whatever) port definitely needs to be open on the gateway to allow OpenVPN traffic through.
I came in to say what was already answered but to add a little more. At least one port will have to be opened for OpenVPN to work. Obviously the default port is 1194. You could change this to some odd port in OpenVPN and your router to make it a little less obvious that you're using OpenVPN.
Also, I haven't looked at how this forum suggests setting up OpenVPN but if your internet traffic is routed thorough your LAN when your connected I would change that. My reason is that my internet connection at home isn't that good 18/1 so I prefer my internet to go through my source connection which is typically faster. With this said, I just leave my VPN connection going all the time. When I come home to my WIFI it disconnects then when I leave it reconnects.
I hope this wasn't confusing as it all seemed right in my head