Typical FAT find...

[S LATHERON (RIP)]

Dont Know much about FAT tractors but that looks like an original Body base, as wheel boxes are still in place, Maybe more work to rebuild it as an original but worth a lot more when finished. Perhaps if you do decide to fit that Fargo body you will adveritise the FAT floor before you cut it loose.A few more pictures would help as well if you do decide to sell it.
Which ever way it goes good luck.