The MU8000 is last years model. It does have the separate input box like the 2018 QLED 82" TV. The NU8000 is supposed to have more enhanced Ultra High Def modes.
As for the legs, there are two sets of holes. The outer set are 60" apart and the inner set are 45" apart. The legs slant out so the total width where the legs stand is 3" more.
The outer leg hole is 6" in from the side of the TV screen, so the leg foot is 4.5" in.