The over was hardly used in the later flagging really only happened with Riverside to connect to the region as Six Flags New England. Most of the flagged parks retained their original names. America, Elitch gardens. Darina Lake etc.
So That name seems extremely far fetched. it's also, at least in my mind, not that good.
Even if they got flagged Who knows what we would see. Shoehorning a DC area doesn't help and when it came to the old Loony Tunes national park more people cared about he costumed characters then the area itself.