So - it looks like it was all before Luffy met up with them after Enies Lobby. Koby’s style of dress hadn’t changed yet, and Helmeppo’s style was still bowl cut and no eye covers.

That said - that’s just when Koby started training with the Battleship Bag concept. We saw last chapter that it took years for Kuzan to catchup to Garp in the quality of hits he was doing - so Koby being able to have a really destructive hit a couple of years into that type of training is maybe a little surprising but ultimately is why Garp had so much faith in him as the future of the Marines.