I agree with a previous poster, both dogs are protecting their owners and amping up through excitement. If they've always gotten along I"d imagine they will continue to get along, just watch them around this kind of horse play.
Regarding grudges, you better believe dogs hold them, my dog got a smack down from a Golden R called Cody when he was a pup, nothing too terrible, just put in his place. Fast forward twenty months and he still remembers Cody and ran him out of a lake last week, where my guy was fetching sticks surrounded by a large group of dogs, including three other GRs. He did not attack Cody as he is NOT allowed carry on that way, but neither would he allow Cody access to the swimming bay. That's a grudge if ever I saw one.