Idler Arm question

Seems to me, I was taught that the idler inner and outer barrels were fused, as we're some control arm bushings.
The thru bolt wasn't to be tightened till all work and alignment were complete, or could cause a "pull".
At that time caster was 0 to -1*.
So the idler was more important returning the steering wheel to center than with today's skosh settings .
fwiw.