Judge OKs $450m deal to end ebook price-hike row. But Apple just won't let it die

"It's not all smooth sailing to payday, however. Apple is still appealing the case and could reverse earlier rulings if its appeal comes through. That's unlikely, court watchers feel, but nothing is impossible in the wacky world of the American legal system."

Is the implication of the above that Apple may not actually pay out if they win their appeal against earlier rulings?

That would be a bit odd since by its very nature, an out-of-court settlement is effectively an agreement to make an ex gratia or "good will" payment to aggrieved partys without admitting to any guilt or wrongdoing. Since they don't admit to any wrongdoing, then the outcome of appeals relating to earlier cases ought to have no bearing on this settlement.