Well being a C50 finding front fenders will be challenging. The cab parts are all the same and the 1967-72 truck are very popular so anything you would find on a pickup truck is being reproduced but the big trucks aren’t so popular so you will need to either fix what you have or search till you find better ones. The difference in the fenders is primarily the wheel well openings and they are taller so you may compare any rusty areas to a pickup truck fender if you are lucky pickup truck patch panels may fix your bad spot.
Good luck and welcome to the BOLT