Some puppies are really noisy when they play, and it sounds like Oscar is one of them
. If Harry looks to be happy with the situation I wouldn't worry too much, but if you think Harry is becoming stressed (doesn't sound like it from your description) you could separate them for a while. Separating them every so often might be good for your sanity and relaxation too
William used to play really noisily with his 2 adult Golden Retriever friends when he was a puppy and used to be at my friend's house for a few hours every day. He was so confident with them and they were very good natured.
Does Oscar socialise with other dogs at all? It could be a bit tricky if he starts to think that all other dogs will be as tolerant as Harry is. He might get a bit of a telling off if he tries the noisy, boisterous play with all the dogs that he meets.