Depends on the law, and depends on the state. If a state has a ban on so-called "assault weapons," but exempts C&R firearms, then the C&R eligible ARs would be legal. I don't know of any state that has exempted C&R weapons from any assault weapon bans, so you'd have to research your own state's laws to know for sure.
How is it possible that my old AR weighs almost TWICE what my friends’ new AR weighs?
I held his and it almost floated away like a butterfly, whereas mine, tied to a rope, could be used to anchor small vessels.