Kind of - it took a while to figure out how to collect aconite, and just time to collect the other ingredients. Once you visit the Doctor's shop and exchange the trade items for the fast poison, you now can use it up close and personal like you do in AC2, or you can use the dart pistol. The dart pistol actually is the same button, but you set the focus on your intended target and then hold the attack button which brings up the aim lines like with the pistol.
As to the fast poison, it works exactly as it's name suggests - instead of stumbling around for a while, your victim begins to swing his weapon almost immediately. In short, it makes for a quicker sequence, but other than that, the regular poison is just as good.