Re-Index Torsion Bars..Just Arms?

My mechanic ran my truck over a rail road track and bent the shit out of the arm at the end of the torsion bar. He said just the arm came off for him to get it back on for now, so why not just re-index the arms instead of the entire bar with the arm attached?

What i mean is the part 34-020 / 34-020z, why not turn the splines on that and not the splines on part 34-061a?

For most people who have issues with rust, the torsion bar is easier indexed by removing it from the socket on the lower control arm, rather than removing the adjuster arm from the bar. Either way, the outcome is the same.