New guy here with a 72 Duster :)

Scody's right. Front brakes/upper control arms were off a '73+ A-body from Pick-n-Pull. If I remember correctly, the 8-3/4 rearend was out of a b-body, so it's a tad wider than the A-body version. You know this, but it's all large bolt pattern stuff.
Nice! Ya someone told me alot of guys swap the whole k member so I ordered pitman and idler arm for a 73. Wrong... Haha the 72 was custom order and twice as much of corse. It should be here today though.