I agree with the others, I haven't voted because I do think it is contagious - if the other bun is susceptible, and there's not really any way of knowing if that is the case.
Santa has chronic snuffles and has lived with Dudley for the past 3.5 years and he has never so much as had a single sneeze. They have also lived close to and for a while with another pair and again, the other two haven't shown any symptoms. However, I don't think I would pair an active snuffler (or one who has regular episodes) with a non snuffler as I don't think you can necessarily tell if it's going to infect the other bun. Many times it probably won't but you might just be unlucky and bond a susceptible bun.