AUX schemtics

Hi,
I just figured out  that the 2 pices pcb have a different pin names for AUX connector.
1 picece: G S AG
2 pieces: G A1 AG

Now I'm using the 2 pieces and I have to connect the X Endstop Switch, but the readme tells I have to use G and S.
Would it be the same with A1 in place of S on the 2 pieces board?

Thanks! 