Romo did not reach the first down marker with his lunge toward the goal line after the muffed field goal attempt and the ball did not come out until his body hit the ground. He may have reached the original line of scrimmage but he was well short of the first down marker.
The only questionable call was what was that linesman thinking when he spotted the ball on the previous play. Fortunately for the Seahawks, it was reviewed and moved back setting up the field goal attempt.
OMG if that call had stood could you imagine all the tin-foil conspiracies Seahawks fans would have had, when you combine that with the last SB.