photo - you'll find when you do that swap that the threaded mounting holes for the hood hinges on the 57 cab don't quite fit the 59 hinges - oval the hinge holes carefully and you can make it work, but you might have a few problems with the hood fit - also you'll find that the 59 frame is about 1.5-2" longer than the 57, because of that little gravel pan below the 59 grill - will need to make some type of extensions there on the 57 or the stock bumper brackets won't work cuz the bumper won't clear that pan
good luck tho, it can work!!
Bill