On the back of the body rail of old RT's there are 2 small hex screws just below the velocity adjuster. What are these for? The reason I am asking is that I just got a used RT and one of these hex screws are missing. I am waiting for some air fixtures so have not gassed up the gun yet. Are these holes connected to the main air access (ie. banjo bolt)? Will I experiencing a leak through the missing screw when I gas up the RT?