What Idler Arm is this?!

Yep, you've got a '73 up spool mount K member. You will need '73 up steering parts but the control arm bushings and strut rod bushings are the same. The lower ball joint should be OK but the upper ball joint will depend on which year control arms you have and whether you have large bolt pattern disc brakes or not. Post a pic of the upper control arm so we can get a look at the socket size on the ball joint.