Note: 녹 and 록 (green) share the same 漢字 root.
Many words that begin with a ㄴ- also have a ㄹ- variant such as in 내일 (tomorrow) and 월래 (originally). Some ㄴ- and ㄹ- words have ㅇ- variants as in 여자 (woman) and 그녀 (she/her).
So what? Or,