Probably not 160...not against Geurrero at least. There was one fight, fuck I can't remember against, where floyd looked pretty damn swole, looked close at least to 160.
The thing with the unnofficial weigh ins are that they are not mandatory. Any fighter can refuse them. They are also not really accurate because they typically happen in the morning of the fight so a fighter can still be rehydrating and still weigh in more than the unnoficial weight.
Floyd is secretive, we know this because he almost never allows footage of his sparring sessions. Most other fighters do but Floyd, call it smart or whatever, he doesn't like his foes seeing what he does. Maybe his line of thinking is he doesn't want them to know what he weighs either. Keep them guessing I suppose.