There are 5 Prototype NES Cartridges of the North America version of Mother/Earthbound.
4 prototype cartridges were owned by collectors, and the fifth was owned by Nintendo of America Inc.

The English translation was complete, but it was never released in North America until 25 years later.
On June 14 at Nintendo World Championships 2015 Nintendo announced Mother was coming to the Wii U Virtual Console, under the title "EarthBound Beginnings".