So I am in the same boat. I ordered a 2004-2007 (apparently not) head from ebay and after installing it noticed there were two oil ports. The one in the back, intake side is leaking a lot of oil.
What did the machine shop do?
I am considering bringing the head to a local machine shop and having them plug the second drain.
I also have heard that in performance engines sometimes they will use bearings to do this.