From what I remember, the guns in the "No Easy Day" book were the camo'd all digi-desert and the 416 had a quadrail. Author talked about having a 10.4 and 14.5" with the 14.5" being more set up as an SPR/DMR with a Nightforce (likely 2.5-10x24 Nav spec as being consistent with inventory of the day)
The "gun used to shoot UBL" is depicted as such:
Mind you, you can't always believe this stuff as media has depicted all the operators rocking the new quad NVG, but individual accounts say more than a few opt'd for their familiar dual-tube setup as not to break the rule of attempting to bring new (albeit useful) kit on an operation...
If you look up Rob O'Neill's pics; several have his gun configured with the OEM quadrail as well. Not to say it couldn't be with an RAHG later on.
Most post-2011 guns are often seen with Geissele's and a few RAHG's, but never much with quad rails.