It wouldn't really have mattered, because they had nothing left apart from their pride. Well, it would have mattered for Tokyo, of course. What I mean is they were already defeated.
Yes, of course, what i meant is that Imo it was better than the Japanese authorities did not know what was the real amount of nuclear bombs of the United States and when they were ready to use them.
Maybe if they knew the truth, their mentality and their pride could have pushed them to make the decision to not give up, even though, as you said, they were basically already defeated.