I should guess that all of them have internal doubts about some of the Bulls***, as all of us must have had, even if with us, it was something as almost trivial as the excessive Rules, rather than actual Doctrine.
But it must have been seriously rattling to them as they formulated the various changes over the Generation Doctrine, knowing that they were being simply reactive to the passing of time, and just making it up as they went along.
I think they know quite well how dodgy the whole thing surrounding 1914 is as well, from the time in the '60's when Carl Olof Jonsson wrote to them, and proved 1914 was totally in error, and then published his Book on it, they must have been inundated with letters along the same lines.
They may fool themselves that, regardless, they are still god's org. but they know they are lying about this.