Some Herero women actually, truly, genuinely wear head gear like this. Most of them in villages do wear the dresses.
Hereros are a particular tribe/ethnicity in Namibia, though I am assuming that this head gear cannot be a pre-colonizarion thing! Other Namibian women do not wear that style of head dress. The dresses may not be strictly Herero, I am not sure.
I gave an old woman a ride to town one day (I picked her up in the middle of nowhere near what must have been her house and took her to the nearest village a good 50 or 60 kilometres away) and she was wearing a mint-green dress just like this, but the matching scarf she had on was an ordinary scarf. I wished I had taken a photo of her, but in my mind it would have spoiled the pleasure of given her a ride for nothing at all in exchange. She was beautiful. She smelled of peppery soap and sat quite nervous in the car at first. When I dropped her off she kissed my hand to thank me (I was so embarrassed) and walked out of the car in front of all the village women holding herself very proud. I gather white tourists don't usually pick up old ladies on the road. When she saw who I was she even stopped waving for a ride and was a little hesitant to come into the car.