Women's Head Covering II

Question

It is true that poskim distinguish between married and unmarried but the gemara certainly does not. To the best of my knowledge the Sepharadi Rishonim and the mechaber also do not make this distinction. Rishonei Ashkenaz seem to have responded to the cultural norm of their time. Do you know of the earliest source to make this distinction? I saw it in a Raavyah. What do you think it means if the Gemara (rishonei sepharad and mechaber) in fact make no such distinction? Kol Tuv,