Taper pin - difference between an386-1-9 and an386-1-9a

I'm ordering some taper pins from ACS for the tailwheel swivel to tail spring.

Based on another post I will be using 2 of the an386-1-9 or 9a.

I looked at the diagram with the taper pin specs but I can't see what the functional difference is between the an386-1-9 vs 9a.

Any advice appreciated.

Thanks

Hole or no hole

The A denotes NO hole in the threads

Thanks

Thanks for your help. I didn't pick that up looking at the spec.