I guess we knew it was, right? I mean, principle photography ended just before SDCC 2013 and, the release is in May, so it makes sense that they are still working on the effects of the film.
Anyway, screenwriter Max Borstein took to Twittwer to update the lot of us on Godzilla's status.
@2014Godzilla lots of effects on a big movie like this, so still plenty to go!
He also speculated on the movie's possible rating:
[The movie is] not rated at all yet. Don't know what it will be, that's up to the MPAA, but if I had to lay odds I'd say PG-13.
So take from that what you will.