The times when a bounty is placed and when it is awarded are apparently important enough to be part of the revision history of a question. However, there is an inconsistency for questions like this one which have not been edited. Since no user edited the question, that information is not visible anywhere.
I'm not sure what implementation makes sense to fix this. Perhaps the revision history should become non-empty when a bounty is placed. Perhaps the information should be placed elsewhere. The point is that it's inconsistent to show the timing of bounty events only when the edit history is non-empty.