The factory never made "quick ratio" (longer) steering arms for A-bodies, so it's not that (they made quick ratio boxes, instead). They made a quick ratio pitman arm for E-bodies, but never made the matching idler arm, to the immense frustration of the Mopar Trans Am racing teams.
They are all for 68-up, that you can tell. Maybe one 68-up A-body idler and a set for a E-body or B-body?