I would think yes to play it safe. Though they may be getting along now, things could change once the milk comes in. If you separate be sure to give plenty of nesting materials.
I'd advise you ask a breeder who has experience or ask on http://www.allexperts.com/el/Rabbits/
The side menu shows the profiles of the people that answer.
Please be aware the BinkyBunny forums do not allow discussion of intentional breeding.