Exactly, this is telling them to cover their breasts. The arab women at the time would use their khimars as a turban and their breasts would show. This is a call to cover the breasts not the hair which was common for the Arab Bedouins female and male.Quran 24:31
"they should let their headscarves fall to cover their necklines and not reveal their charms except to their husbands"
the Quran uses the Arabic word khimar to refer to women’s headscarves