No, they added standing room only tickets, which are only sold for games with very high demand. That's how we're getting new records. No new seats were added this year.
That said, there are architectural drawings -- and the whole building was designed to accomodate -- the 300 level above the 12th man flag to be filled in. That would bring capacity to 72,000 which is the minimum for a Super Bowl.
There are also sketches for filling in the Hawks Nest, which frankly given how much that new building blocks the city skyline, wouldn't be a big deal now but would have been annoying years ago i.e. there were cool city views from my seats up until this season, but there aren't any more, and so in the past I would have objected to filling that area in, but now I could care less.
BTW, the number you referenced is almost exactly the number that would be added. Official seated capacity is right around 67,000 and the fill in at the 300 level in the south end zone would bring it to 72,000.
Will this happen any time soon? Hard to say. I would think actually it mostly depends on how the NYC Super Bowl goes... if people like the fact that weather impacts the game and it's likely that other northern cities could get Super Bowls, I could see them adding the seats in tandem with putting a bid in.