The new Maine 2nd district is slightly more Republican, though certainly not to the extent that Romney could win it outside a non-close election.
So it is or is not really at risk?
Based on the polls by CD I've seen, Maine-2 is likely going to be 5 or 6 points more Romney than the state, but the polls also indicate Maine as a whole will have a double digit margin for Obama, so while Maine-2 will have a single digit margin, it's safe Obama unless the third debate is as fruitful for Romney as the first one was.