Hi Gregory,
A warm welcome to the bolt. The area above the windshield is a very tricky spot to work on so I would not fault you for cleaning as much rust as possible and filling the area. Be sure to use a waterproof filler like all metal or similar.
That said, the repair will eventually fail. It may look fine for years but if you will be putting a many thousand dollar paint job on the truck that you want to last for 25 years or more then the best way to go is repair the area with new steel.
By the way, I don't know how many people will see you post here. If you want more feedback go ahead and start a new thread.
And finally be sure to post pics when you can. We all love pics.
