Modern as in brand new or close is one thing, I believe the donor under consideration is from the early 80's, modern in comparison to a 52 truck, but nothing special.
You're right that my chassis donor isn't new, but my Granddad hauled a 32' 5th wheel, and a kit car with his '73 3/4 ton Ford This donor is a 1 ton, so I would hope it can handle the load better. And I do plan on making upgrades to the brakes (rear discs), and suspension (bushing and air ride), so it should be good to go. But do me a favor, and keep me honest.