Hmm. Ever used NOS fenders?
Usually they don't fit. That's why they were in the parts system.
Chrysler's Replacement body parts were almost always the defective parts that couldn't be used in the assembly line.
Welded together crooked, didn't pass the test, so off to the parts warehouse.
Not wanting to dampen the enthusiasm of the original poster, because NOS parts are a great score regardless, but be aware that you may need to drill some spot welds, and reposition some pieces. And look at the hood adjuster insert. Some NOS fenders have a square nut instead of the round "rosette" shaped insert.
As for the rust removal, don't let anyone near them with a sandblaster. No electric tools either!
Sanding bare by hand or gently with an orbital, a hand spot blaster for pits, and metal prep acid used properly is a safe way to ensure no damage.