Kinda depends on the Model ,202,33, 404,606 ,ZEBCO ONE and more .
BUT the original ZERO Bomb Company Reels had only 1 , the FIRST 202 had 3 and only 4 detents on the Spinner . Through the years like many or all Companies they cut costs by lightening up stuff . Zebco put 1 rivet ,2 rivets ,slotted the foot into the plastic and GOBS of other stuff .
Here is the FIRST year with the Box
Horrible picture but here is the Spinner . Notice the detent is curved instead of Toothedand there were only 4 of these detents on the spinner