Sorry for my bad English.
The two bodies are relatively different:
Nikon D810 mirror box are in plastic where the lens mount are connected
and this is the D800 mirror box
here's what happened to D810:
and my friend D810
Everyone says the D810 body is the same as before (D800) without showing any pictures of the new magnesium body (unlike in all the pictures of D800 magnesium).
I think it's different enough certainly worse at a higher price.
Well done Nikon!