I think from the rivets that the frame extension is either factory or at least old, although if factory I would have expected more than just a couple of rivets on each side.
Not sure on the fender size. I know that if it was a 47-55.1 truck the 1 ton front fenders would be the same as the 1/2 & 3/4 ton trucks. I'm sure someone else will be along to answer that question.


Kevin
1951 Chevy 3100 work truck
Follow this saga in Project Journal
Photos
1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car)
Busting rust since the mid-60's
If you're smart enough to take it apart, you darn well better be smart enough to put it back together.