Is this normal?

The grease sling is a good sign that the previous owner actually took the time to get under the truck and do maintenance and grease those u joints.

 

That frame looks really good. Notice, there is no delamination back by the front of the leaf spring mount (in the frame). You also have had the dealer applied coating inside the front boxed section by the looks of one little piece of channel they add. If I'm guessing, and I am, when you compare the amount of rust on the rear drums and some of the smaller brackets, I suspect the frame has been replaced.
That frame looks good from what I can see.
Enjoy your new truck!

 

https://www.youtube.com/watch?v=B2LLB9CGfLs

 

DAYYYYUMMMM for a BC truck, a truck of that age, that truck looks damn near perfect! You better go shake that fellas hand that wool waxed it every year or you'd have a truck with a shite frame! I live in Northern Michigan, and looks just as good if not better than mine!!