1968 rear distributor contact breaker drive shaft end play

Please, must the CONTACT BREAKER DRIVE SHAFT has end play.
Must have the CONTACT BREAKER DRIVE SHAFT an end play?.
With end play of the shaft both sprocket and I. E. rotor have longitudinal movement and there are not firm in their rotation.
I think that needs no end play!
Thank you.
Piero

If you have an old automotive dwell meter, it will tell you if the timing is wandering around. Or even just a strobe light, you will see the timing vary around if the timing is not stable. I would think you want all the play out possible without binding.