Welcome BIGSKYGMC Louie!
You may wish to start a separate thread for what sounds like an awesome truck find!
Look under your seats in the springs and you "may" find the "build sheet" that will have lots of detail about your truck. They are not always in the same location or even removed already so good luck.
Hope to see more photos of your truck.
Here is a build sheet on a truck I used to have and a paint chip page with some information that may or may not be correct for you.