Can anyone tell me if this is the same engine as the Novarossi Keepoff 21-4?

"This is the NovaRossi Mugen Beat Plus 21 BT4 'Keep-Off' race tuned offroad 4 port long stroke buggy engine (part #NV21BT4P). This engine is based off the Novarossi Keep-Off 21-4 which created more linear power band, higher top speed and great fuel mileage. It is finished off with the traditional Novarossi purple head with Beat graphics (Note: Engine includes Turbo Glow Plug)."

If not the exact match, anyone know the differences?