Will - I just sent you a PM but you can find some pretty good info on page 4 of Jim Carter's 34-46
Virtual Catalog . This page lists the differences between the trucks and also provides more info that will help you out.
About the fenders - I haven't seen any repo metal ones listed anywhere. If I were you I would post in the parts wanted section of the Swap Meet. You might also give
Brad\'s \'41-\'46 Chevys a shot as he has an ad up in his parts for sale link:
1940-46 1/2 and 3/4 ton Chevy and GMC, Rear metal fender, passenger side, not great shape but not bent up, needs some repair at running board connection spot ( flat stock to be welded in).....$220.Give
Patrick\'s Antique Cars and Trucks a call. If they don't have any they might know someone who does. You can find their link in the Links section of the 'bolt.
There is a guy out in California who has a warehouse full of NOS parts but I forgot his name and number. I believe I obtained it from Jim Carter.
Take a look at my fender section on "My '41" link below and you'll see that mine were not in the best of shape but are repairable. I personally think you would do better finding a good body guy to patch them up for you.
Good luck and welcome to the 'Bolt