Perhaps we are using a different notion of 'confidence'. The uses of that term that I am familiar with have a separate specific meaning apart from probability. Confidence to me implies meta-level knowledge about the potential error in one's probability estimate, intervals, or something of that nature.
So in your analogy, I can't be confident about any properties of an unspecified process. I can of course assign a low probability estimate to the proposition that this unspecified process won't value paperclips purely from priors, but that will not be a high confidence estimate. The 'process' could be a paperclip factory for all I know.
If you then map this analogy back to the original SIAI frame, I assume that the 'die' maps loosely to AGI development, and the 12 is AGI's values being human values. And then no, it does not make sense to be confident that the roll won't be 12, given that we supposedly don't know what kind of die it is. It very well could be a 'die' with only 12s.
Priors are really just evidence you have already accumulated, so in reality one is never in a state of complete ignorance.
For example, I know that AGI will be created by humans (high confidence), humans create things which they value or things which help fulfill their values, and that humans for reasons both anthropocentric and economic are more likely to thus create AGI that shares human values.
I don't think it's useful to talk about whether we can have confidence in statements about the outcome of an AGI process while we still disagree about whether we can have confidence in statements about the outcome of rolling a hundred-sided die.
So, OK.
Given two statements, P1 ("my next roll of this hundred-sided die will not be 12") and P2 ("my next roll of this hundred-sided die will be 12"), I consider it sensible to be confident of P1 but not P2, you don't consider it sensible to be confident of either statement. This may be because ...
It's just occurred to me that, giving all the cheerful risk stuff I work with, one of the most optimistic things people could say to me would be:
"You've wasted your life. Nothing of what you've done is relevant or useful."
That would make me very happy. Of course, that only works if it's credible.