When I bought this barrel online I was not aware of the drill holes it had for the gas block. The seller had the gas block on it when he took pics but did not send the barrel with the gas block. I have magpul hand guards and I am trying to find a railed gas block where I can add a flip up front sight and hide these drill holes.  I need a gas block and front flip up sight that I can use with my eotech. If you look real hard, you can see the drill holes right in front of my gas block. The scope is no longer on it I now have an Eotech.

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Many of these should cover the holes.  However, the top railed gas blocks must use a gas block mount front sight.  A standard rail mount front sight, like the YHM QDS or TROY, will not work on the lower gas block rail.**  
On the flip up front sight with bayonet lug, the mounting clamps measure .475 inch wide, front and rear; from rear face to front face the sight measures 1.892 inches long, and the clamps measure 1.412 inches center to center.  The back of the sight should be around .031 off the ledge rearward of the gas block port so you can use these measurements to see it it will cover your taper pin holes or not.

** MI makes a HIGH railed gas block that will put the rail on the same plain as the upper's rail. link  However, I do not know the length of it or if it will cover the taper pin holes.  This one should cover the taper pin holes as well as give you a flip up front sight.