I just removed the upper handguard to see. No leakage.
As I mentioned, I took a piece of scrap cleaning rod, and turned it in the lathe until it just fit the gas block. Used a drill, and spotted both sides through the gas tube retaining pin hole. Removed the plug, drilled from each side until the holes intersected, and the drill passed through. I did it this way to insure that the hole didn't run off on an angle. Replaced the plug, tapped the roll pin into place.