A fold-out small tab with a hole in it is as much you will find of a 'leader' on 120 film. Rolls of 120 film have a series of dots or numerals (these vary among manufacturers) that precede the start mark a vertical line or word to that effect with the first frame beginning soon after. When the start mark is located and matched to a dot or marker in the film chamber, it is then advanced carefully until the number 1 is indicated by the wind on mechanism. When finished, the end of the roll is a reversed leader that is normally taped back against the roll before storing it ready for processing.