Forum:Is MG Saga Vol.2 canon? (quick reply please)

Is MG Saga Vol.2 canon? Because I've encountered some errors in it, like Solid Snake being the leader of Tankers hijackers in MGS2, and Navy dispatched Marine to disfuse the threat (Marines was already there before the ship was hijacked). Can it be regarded as canon even when this errors are there? Or this aren't error, I'm wrong and missing something?