If they aren't altered, they can't be housed together or bonded until they are 4-5 months old and altered. Even if you are "guaranteed" they are the same gender, its best to be safe for a couple months and keep them separated.
To be frank, I would just get 1 bunny and bond with it, and then add another later down the line if you decide its something your bun needs. It'll be cheaper up front, for vet costs, and it'll also be much less stress initially, and more fun. I tell ya, if I didn't have the bond I did with Sam, I never would've made it though bonding her with Lady
ETA- if there was a bonded pair you can rescue, that would be good!