No, you should nurse them longer, I'd say around 9 weeks to 10 weeks. The baby bunnies must be mature enough to fend off predators and scavenge for food. That is for a wild bunny. If you have a household bunny, I would recommend giving them away to a neighbour or close friend, that way you can visit them often until they are fully adapted to their new surroundings.
A different answer: The babies may start to wean at 4 weeks, but it's best to leave them with the mother until about 8 weeks. Then, it's a good idea to keep them for at least another few weeks, socialising them and getting them ready for adoption.
When you give away or sell a rabbit, it's your responsibility to screen your customers and educate them about how to care for rabbits. You should prepare handouts with basic information, and a list of websites and organisations they can go to with more detailed questions. Many breeders recommend always charging money for your rabbits, because some people don't take things they get for free very seriously.
Pet rabbits are overpopulated. Animal shelters all over the world have pet rabbits looking for a home, and many of these rabbits will eventually be killed by the shelter because no one has adopted them. Consider spaying/neutering your rabbits instead of breeding them.