Search for emacs (the word, not a tag). On the second page of search hits, you will see an entry for this post which has an accepted answer (from some time ago), but the search-hit entry does not indicate acceptance.

Seems like a bug.

@rolfi points out that this is the behavior to expect currently: status quo. So if you do not want to consider this a bug then please consider it an enhancemnt request:

Show users the following in all search hits (i.e., including answer hits):

• Whether the question has an accepted answer.

• For a particular answer search hit: whether that answer is the accepted answer.

I'm guessing that wouldn't be too hard, and it would help users.