Looks like you are asking the right questions. I'd be really curious to see if they were neutered. If not, then it is certainly possible that any move from their normal environment could cause territorial issues.
One year is fully adult, so isn't at all too young to be fully bonded. They couldn't share an enclosure unless bonded. The real question is about the neutering. If neutered, then it is more likely to be a solid bond. If not, then the bond remains iffy.
I'd also be curious as to why they've been together since one month of age. That is too early to have been taken away from their mommas. Possible downsides would be that they missed out on some important antibodies from momma for not having been with her a full 7-8 weeks, or they came from a bad breeder with rabbits of questionable health.
That said, they could work out. Just know that their relationship may change - especially if not neutered - when they move to a new home/territory. You may need to be prepared to separate them (even if just temporarily) if they start to show aggression to each other.
I don't mean to sound discouraging. I, myself, like to know the worst case scenario before jumping into anything. That way I'm prepared.