Games have been getting "post-gold" updates and day-one patches for like a decade or more.. This is nothing new.
I don't understand the fixation of catching people in an alleged lie.. What's the difference whether they genuinely underestimated the time required to do something _they've never done before_ (testing on so many platforms) or whether they actually, completely unreasonably, decided to lie to everyone about having gone gold?
Not to mention that if they hadn't actually gone gold, there are tons of outside parties who would probably have realized it pretty quickly (given the production work that happens), and we'd all have found out anyways.