Does he have big tufts of hair on his paws? My Maine Coon mix looks exactly like a full Maine Coon except she's a little smaller than the average Maine Coon. Her brother is a big one though!
He is quite alike a Maine Coon. therefore not said he is a MCO. MCO is a natural breed, ie they were purebred from a natural population of cats. And this natural population, the grounding stock so to speak, are still living out there.
so he may be a random look alike, but he may also be one of the "country cousins".