You would have to buy the entire outer & inner roof if you go new. American Classic Truck has both, $250 for the outer & $209 for the inner. Thats why I bought the use roof. JIMBO shipped it DHL. I don't remember how much it was for shipping, but I think it was just under $200 for the roof and shipping. Your truck looks in pretty good shape. Rust in the usual spots. Your rt. fender looks like my left one did. I had to section the lower rear and the front above the headlamp because of a big dent.
I hope this info helps. Anytime I can help let me know. I don't know everything, but between everyone on Stovebolt you can find out anything you need.

1957 Chevrolet 1/2-ton Stepside LB in the Gallery
My Photobucket shots

The person who has nothing for which he is willing to fight, nothing which is more important than his own personal safety, is a miserable creature and has no chance of being free unless made and kept so by the exertions of better men than himself." - John Stuart Mill (1806 - 1873)