No, it's not immediately obvious whether a post is an edit to a question or an answer. In fact, here are some screenshots of edits against questions and answers so you can see for yourself.

## edit against a question

![enter image description here][1]

## edit against an answer

![enter image description here][2]

The only way to know if it's an edit against a question or an answer is to open up the question (by clicking the question title, which is shown in both cases) and checking.

  [1]: https://i.sstatic.net/eX839.png
  [2]: https://i.sstatic.net/E3j3e.png