No undercoating is fine unless you drive your truck anywhere but your paved driveway. These old trucks have no inner fenders like the newer ones. If you do drive your old truck, I guarantee you will eventually get a large piece of gravel or a small stone caught in your tire tread and then flicked up in your rear fender well. Without any type of undercoating, chances are you will get a nice star in your paint job. I realize that undercoating will not guarantee protection, but it could sure minimize damage. 56PICUP was a rock victim so...just a thought.
