Goins has posted a .767 OPS in the second half. It depends on whether or not you believe he's made improvements or just been lucky. Colabello's babip is clearly high, but he's also hit 14 homers in just over a half a season's worth of at bats..you can't totally discount that level of production. Pillar has gotten marginally better over his previous year's numbers.
I'm not saying these things were specifically due to Jacoby...maybe things just started clicking for these guys and would have regardless of who the hitting coach was, maybe jacoby did have some influence, perhaps it was something a player passed on that helped these guys...these sort of things are hard to judge.