I can only judge what Romney would do by his past actions, not by what I would like to think or my feelings about Obama.
Not only does Romney have a history of signing anti gun legislation, he has a history of changing his opinion on everything depending on how the media portrays an issue.
I don't think it would have mattered who got elected. There was a mass killing, the media got hold of it, and the politicians are doing what politicians do.
As to Obama's call for gun control, that's what is expected of him by the media. He's a politician. He knows he can't do a thing unless a bill is passed.