That's my take on it. I don't think they showed the clone infiltrating the demon's mouth though, so it's possible that he left at least one clone inside of the 4-tails when he made him puke.

Here's a question, did Naruto ever develop a faster way to gather sage energy? I remember him saying that was the first item on his list of things to master but I don't remember an obvious point at which we were shown that he managed to do so.