I'll put it this way - save for a handful of animated movies over the years, I can't recall of a singe other live-action movie ever releasing a three-minute trailer five months before its theatrical release. Literally only two or three movies a year even have three-minute trailers, as the MPAA allows each studio only one theatrically-shown trailer per year to be over two-and-a-half minutes, and those almost always are released as final trailers way closer to the film's release. Granted, this is Star Wars. If ever there was an exception, this is it. That, and Disney may be looking to make a big statement in response to all the negative reshoot press of the past couple months. So I get it, and it's definitely not out of the realm of possibility.
Honestly, my gut says it's going to be more of a hybrid; not a true trailer, but something more than a behind-the-scenes featurette. Basically, a lot of new footage intercut with talking-head interviews and what not. But look, no one wants a full, legit, three-minute Rogue One trailer this weekend more than me. I would be over the moon. It just doesn't seem likely, given all the evidence. Will gladly be proven wrong, though.