When I first started looking for a '41 thru '46 1/2 ton, I saw a few real hunks of crap sell for $1,000 to $1,200.. no rear axle, no front drums, no motor, no tranny, body in worse shape than your latest aquisition.. don't know if it was shill bidding to drive it up or just two guys decided they wanted it, lived close enough to pick it up, and went nuts.
I've seen alot of good trucks sell cheap on eBay and i've seen alot of crap trucks sell for crazy money.. sometimes there dosen't seem to be any rhyme or reason to it.
I'd say on average, you got yourself a solid $800 to $1000 parts truck for your fuel and time to get it and your $400 winning bid.
Being a Utah truck, i'd guess you should have little to no rust thru.