14 bolt corporate axles for 1st gen blazer

[Jvan]

I've come across a local sale in Craig's list for the front and rear axles from a 85 suburban 3/4 ton. The ratio is 3.73. He's asking $200. Is that a fair price and would they swap into a 1st gen 72 Blazer. I don't know if they have positraction or not and the they look alittle rusted on the shafts but I've only seen a picture. What should I look for and avoid? I'm getting parts to do a restoration so this is not a must have but a stronger upgrade for the future.