AFR 185 heads - what is this hole for?

I was attempting to isolate a ticking sound that I have been assuming was noisy rockers. I wanted to be sure I didn't have an exhaust leak before getting into adjusting my rockers for nothing, so with the engine running, I put my hand down around the headers to feel if there was any air pressure. Sure enough, there was a bunch of air just puffing away out the back of the passenger side head. I had assumed it was a loose header bolt, so I snugged it up (wasn't even loose, plus I am using Percy's aluminum header gaskets, so should not leak). I felt around again for air pressure and it was still there and just as strong. I was able to isolate the air coming from the back of the head. So I went back to my picture archive from when I was doing some transmission work last year and have the following picture:



You can see in the picture a dark stain indicating a leak, so am guessing this is the hole the the exhaust is leaking from. I searched the AFR website high and low for a reference as to what this hole is supposed to be used for, but could not find anything. I will call AFR's tech line tomorrow, but was hoping someone here might be familiar with it since many are running these heads. I'm guessing it's a smog port for use with later model 5.0 engines, but want to be sure. Am also assuming I can just put some high tem RTV on the right sized bolt and plug it. Any info is appreciated.
http://memimage.cardomain.com/ride_images/2/3647/3741/21616870139_large.jp

Thanks for confirmation. I did see thermactor plugs listed on AFR's website and agree, it looks like they are already screwed in there. I'll check tomorrow, hopefully it has just gotten loose. I will apply red loctite and tighten that puppy down and hopefully ALL my problems will be solved... Until the next one comes along...