No you don't need the o-rings.They are to eliminate clutch chatter on the stock clutches.The aftermarket clutches have more material on the friction plates.If you hold the stock ones beside the aftermarket ones you'll see what I mean.
So ledofthezep is right,but you don't have to soak them for 30 min.It only take about 5 min. But it doesn't matter if they are soaked longer.Just put some oil in a zip lock bag then put in the clutches,seal it up then start taking the old ones out,by the time your ready for the new ones they will be plenty saturated with the oil.