At 1st level, a greensting slayer can expend 1 point from his arcane pool as a swift action to add 1d6 points of sneak attack damage to his next melee attack that round. The attack must meet all of the usual prerequisites for making a sneak attack, as the rogue class feature. For every 4 levels beyond 1st, the amount of sneak attack damage dealt by this ability increases by 1d6 (to a maximum of 5d6 at 17th level). If a greensting slayer gets a sneak attack from another source, the bonuses on damage stack.
Does Greensting Slayer Magus 5 have Sneak Attack 2d6, specifically, (assuming skill ranks are met and they chose Mage Hand as a Cantrip) would they qualify for the Arcane Trickster Prestige Class?