The upper arms are the same, I believe (although I could be wrong) the lower arms are the same. The rotors I wouldn't re-use, the calipers are probably better used as cores, the prop valve won't help if you're going rear disks, and the booster is a big ? depending on its condition. So, the spindles are really the only thing you're getting out of this deal that you really need and can probably use. I'd keep the fenders, even in not so great shape you could get new spindles for less. And considering that you don't need e-body spindles specifically, I'd pass (A-body spindles '73-'76 will work, so will the later F/J/M body spindles, despite claims that they won't).
Also, the year of the spindles makes a difference. If they're 70-72 spindles, they'll only take the early type rotor, which are harder to find and more expensive. If they're '73 up spindles, you can bolt on 11 3/4" rotors from a later model mopar (cordoba's, diplomat's etc, 77-81). Here's my conversion to 11.75" rotors...
http://www.cuda-challenger.com/cc/index.php?topic=56565.0 Just food for thought. I'd sell the fenders and use the money to buy new spindles and 11.75" caliper bracket's and put the left overs to getting the rest of what you'd need.