4 weeks is sometimes to young to know. (I‘d personally would wait till they’re 6 weeks)
However in the future, please separate your buns.
Rabbits are in infamous for hurting (possibly even killing) the other rabbit. (After/During adolescence and they clearly aren’t there yet lol)
They become territorial after they reach adolescence (3-6) months.
It seems that like they are friends currently this is known as a “baby bond” and when they grow older their false bond will break.
Spaying/neutering will greatly reduce territorial behaviors.
Additionally, if you do spay them (which is highly recommended for pet rabbits).
You’ll need to bond them. However there is no guarantee that they will bond.
In that case they would need to be housed separately. 🤍
I stand with my original vote of 2 bucks and 1 doe. However, sexing in person is a lot easier / clearer and it could end up being 3 bucks like @SableSteel said. But there is definitely at least 2 bucks in there!