No, I usually add my fruit to the secondary unless I'm making a lambic. I usually add about 10# fresh fruit that is macerated. Seeing as peaches have a more subtle taste, you may want to bump it up, depending upon how pronounced you want the peach taste. You may even want to leave the peels on to add to the flavor profile (not sure what it would do though, seeing as I've never made a peach fruit beer before). Just make sure they are rinsed and visibly clean before you add them.