The US Govt (I believe SOCOM) gave development assistance $ and knowledge to FN for the SCAR project, making it SME (outlined above), so regardless of chamber or stock, it isn't eligible for commercial civilian export. Never was.
Nothing 556NATO or 7.62x51 NATO has been approved for export since at least 2005, with a further notice/crackdown issued in 2007 or 2008 (can't remember), the further notice was to say that misrepresenting items as 223 on licenses which are actually stamped 556 would lead to seizures/charges/fines, which is why items have been marked/configured differently since that point. This also covered flash hiders and collapsible stocks, all items mentioned in the US Munitions List, items covered by this list cannot be exported for commercial (civilian) resale.