FN can sell ARs to any one they want; they just can't use Colt's licensed Technical Data Package to produce those parts for civilian consumption. Colt's TDP is not just dimensional specs, it also includes specifications for material sourcing, production and assembly methods, as well as fixes for design issues.
Do you have a link to that? I've heard for a long time that Colt prevented FN from selling ARs commercially in the US once they got the M16 contract. At one time FN did sell ARs in small quantities, even a few semiauto lower receivers have turned up. But today they don't have an AR out there and I'd sure expect one if they were free to sell them.