I would say it can be both, it really dosen't matter, and when he gets older you can call him Mac.
Mackenzie \m(a)-cken-zie, mack(e)-nzie\ as a girl's name (also used as boy's name Mackenzie), is pronounced ma-KEN-zee. It is of Irish and Gaelic origin, and the meaning of Mackenzie is "fire-born; son of the wise ruler". The name's development was also influenced by Cainnech, meaning "good-looking". Originally a surname and male name, but actress Mackenzie Phillips has made it prominent as a masculine name for girls. See also Kenzie and Mc- names.
sam- boy, mackenzie, and another girl i forgot name youngest daughter is called Claire
Aggie MacKenzie's birth name is Agnes MacKenzie.
Mackenzie Rosman's birth name is Mackenzie Lyn Rosman.
MacKenzie Porter's birth name is Mackenzie Lea Porter.
Mackenzie Phillips's birth name is Laura Mackenzie Phillips.
Mackenzie Mauzy's birth name is Mackenzie Grace Mauzy.
Kelvin Mackenzie's birth name is Kelvin Calder MacKenzie.
Kent MacKenzie's birth name is Kent Robert MacKenzie.
Midge Mackenzie's birth name is Margaret Rose MacKenzie.
Niall Mackenzie's birth name is Niall Macfarlane Mackenzie.
Patch Mackenzie's birth name is Patricia Jean Mackenzie.