How do you usually sanitize? I just rinse with water, crush, press and treat the juice with sulfites. Dunking the apples in sulfite before crushing will still result in sulfites in your cider, so I don't know what the difference would be. Are you trying to get natural fermentation?
With good apples, the contaminants will be on the outside. Just make sure you don't have damaged ones in there. There will also be lots of biological stuff on the press - although not if it's brand new.