Steering Column / Shaft Position

[Six862m6]

New question for those who might know.

While replacing my turn signal switch in my '68 GMC, I of course had the steering wheel off and the top part of the column apart. (Old turn signal switch still installed in pic)

I noticed this small line notched into the top of my steering column's shaft. Can anyone tell me if this is supposed to be the indicator for placing the shaft/steering gear in the dead center position? As in this line should be facing directly forward and then changing the toe on the front wheels to be straight/aligned with this position? Also I would then say that the steering wheel adapter would of course align with this so that where it says "top" would be at the top and the steering wheel centered as well.