When a bounty is automatically awarded, it goes to the first answer. Is this still the case when an answer was older, but was edited more recently by the original answerer than a newer answer with the same score?
The bounty, if awarded automatically, goes to the oldest answer in case of two or more answers having the same score (of at least 2) at the end of the grace period. This awarding is independent of when the oldest answer was edited.
Also, please note that the highest-voted answer posted after a bounty was started on the question is considered for automatic awarding. It is in the case of a tie between two or more such answers, that the oldest answer is chosen for the award. For more details, see How does the bounty system work?.