This is it and yes it's a slickside upper. He's not so worried about the deflection, he's more concerned about the brass hitting the side of the upper and leaving marks on it! his dad was a gunsmith and he's pretty picky about his guns but instead of watching his dad when we were kids, well you know we were into other things.
http://www.dpmsinc.com/Case-Deflector-for-the-A2-Upper-Receiver_p_1655.html