spark advance lever

[Willynch]

New to model A. I have a 30 Tudor. I am reading about the 10-11 "notches" that are felt when moving the spark advance lever on the steering column. I do not feel any "notching"; just smooth movement.

I am assuming there are nubbins that have been worn away over the years. Where would these "nubbins" be located?

Steering column? Engine side of firewall where spark advance lever links to the mechancm going to carburetor?

Just curious. Not sure if this a necessary feature