I know relatively nothing about working on a classic or anything else that is includes.
Sounds like you may have bitten off more than you can chew. I hope you have a lot of ambition to keep you going. Most projects that get stripped to the frame by first timers never get put back together. Good luck.
Now about your question. What to do about the pits depends on what your truck will be used for. If you are building a working truck don't worry about the pits, unless of course it is rusted through. Then you have a different problem.
You have come to the right place for help. Most of the questions you'll encounter have already been answered. Use the search feature. You'll find a plethora of info on these old trucks.
Welcome aboard.
