Yes and no. You should not need to undue the serving to move a peep. It should be way higher than that. Now if the peep is held in place by serving thread than that is easy. Most times you do not even need to undue the thread. Just wax up the string and push the top thread up, move the peep and then push up the thread below the peep. Keep doing this until you find the correct spot. If the peep doesn't line up at full draw, just twist the string a bit or twist your D-Loop to align the peep to your eye at full draw.