Any dealer should be able to do the warranty work, but unless you have a real good story to explain why you didn't buy it from them--and they are convinced you will buy your next one from them--expect them to not really fight for you.
They will be reimbursed from kabota that same no matter where it is bought, but when my tiller snapped in two the first time I used it, kubota said they wouldn't cover it and my local dealer wouldn't even spend time on the phone trying to convince them otherwise. He said he didn't want to spend his money paying his employees to talk on the phone and send pictures to kubota.
I had made the mistake of letting them give me a quote on the tractor. They were high by a few thousand, and thereafter not in the mood to be helpful. So, yes you are suppossed to be covered, but I would have the trailer available if need be.