It's not making it "official" that matters, but explaining exactly what happened. Too many times, I've seen deals come undone because they weren't really deals at all.
Oddly enough, just today, the CEO of a company I follow claims that a company that acquired a "controlling interest" in it and the person behind that company was made CEO, was "only an investor, no more no less". The about face came about because someone went to their offices and found the place stripped of all signs they existed.