A u bolt is a bolt bent to a U shape. The lock washers should be replaced if they are not still "spread". Other than that, you can reuse any bolt in it's former place if still in good condition. Those quotes are BS+. Rolled threads are not prone to any more "distortion" than cut. The washer keeps the nuts tight. You don't get accurate torque with an impact, that we all know. You use a torque wrench. The part about salt, road and rust is the "good condition" part. It never "hurts" to use new bolts if you have the money and if you believe they are better. IMO: replace, in a manual, means put the stuff back on, unless they use other modifying words like "new". The 55-59 Truck Manual, under "spring replacement"/removal and installation, does not use the word replace for the U-bolts, it says "install U-bolts". "Install nuts on U-bolts and tighten firmly".
