Green-blotched snow corns have been accused of having Intermontane (Emory) blood in them by some for at least 2 decades. It's never been really proven, either way. It's possible, but that's a big pill to swallow. If true, then all corns likely have some emoryi blood in them by now from the outcrosses done with those guys over the years.
In short, nobody can answer that first question without seeing the snake (if they could for SURE even with seeing it). To the second question, if it is a regular green-blotched snow corn, then it has the SAME chance of being mean or docile as any other regular cornsnake out there. Handle it properly, and it'll grow into a great pet!