57 Frame question

[pmiller]

I have a 57 GMC pickup and am trying to figure out what is wrong. The VIN says that it should be a longbed, but the wheelbase is 114" and the bed is from the wrong year. The engine is the correct 347ci, but am unsure if it is the original. Can anyone tell me if the frame rails from a shortbed were all one piece or if two pieces were welded together? I think that either someone cut the frame to a shortbed or put the cab on a shortbed frame.