If they've made such announcements, they're a well-guarded secret. There's nothing to support this on either company's corporate web site (both have "press release" pages), nor any mention of such in the Wall Street Journal. (Which does have a decent op-ed piece by John Lott -- published yesterday, I believe.)
Anti-gun folks are picketing Walmart to persuade them to stop selling "assault weapons," according to the HuffPo
. And there are rumors, on some websites I'd call less-than-reputable, that Dick's is refusing to fill some orders. Other than that -- nada.
Not that they couldn't do so, but there's no real sign that they are. I can see, though, why the owner of your LGS might wish it were so. He's probably pretty sick of people who come to his store to look, get his expert opinion, and then go to a big box to make the purchase; especially when the market's as hot as it is right now.