They barely scored more than they allowed. They were the product of winning a ton of close games. It's unlikely that will continue going forward.
Check the 2nd half of last season when it comes to run differential.
And yes, it is unlikely that will happen, but the 1st half was the fluke if that's the word you want to use. Once Machado and McLouth got here our defense went from bottom of the league to one of the better ones, our pitching also improved a lot come 2nd half when Tillman and Gonzalez came up.