I had a partial RBB diagnosed on my Australian Class 1 about 6 years ago. The Doc told me it wasn't a big deal and then went on to explain that a LBB had far more implications than a RBB.

When I came to do my FAA Class 1 a few months later, the Doc made no mention of anything out of the ordinary on my EKG. I explained what had come up on my Australian medical and he simply said "well it's not there now".

It's never come up since, either.

Best of luck.