When I was in Vegas in April, I went to Citadel Gun and Safe (off the srtip behind Caesar's Palace) and they had the Larue flip mount for $150 U.S. (to go along with the 3x at $449 U.S.).
And basically you'd have to order one from the U.S. anyways, plus all the crap that goes along with that. I don't see $100 for a quality one to be an issue. If you had more of them, you'd have gotten a PM from me by now.
Back to my original question though, who do I have to kill for some Prime lowers?
And it's still a nice gun.