Right, same breed, just different varieties. It makes sense about the coat, most likely why some people prefer the smooths. I've seen several in obedience and agility, lovely dogs.
Same here, most of the rough Collies I've known have been show bred and they were all pretty mellow as adults. Seems like most rough Collies are either bred for show or pets. People who want to really work Collies usually seem to go with the smooths.
Your pup isn't well aware of anything at only 10 weeks old, he's just a baby. Collies are generally very smart and don't have a much of a prey drive. Just keep up with the training and keep them separated at times when you cannot supervise.
Eventually they will most likely get along just fine :)