I'm not as up to speed on awards; but can the DSC be recended and upgraded to a MOH?
I don't know how that works.
It happened with 2Lt Vernon Baker, for his actions in WWII Italy while serving with the "All Negro" 92nd Inf. Div. It was determined that his efforts would have earned him the MOH save the pervasive racism of the era. He recieved the MOH in 1998 or so.