Yes, I think it is, with some caveats (see below). Basically, it's noise, distracting from the real information in the answer, and it needs to be removed, just like greetings and signatures: Should 'Hi', 'thanks', taglines, and salutations be removed from posts?
@Sonic is right, many people have an aversion to 'necro-posting' based on their experience with other internet sites, but Stack Exchange even has two badges to reward this behaviour, so excuses are not needed.
Please keep in mind:
- As with all edits, try to improve other things in the answer as well.
- If the Q&A itself haven't been active for a while, it's not really necessary to bump the question again.
- If you don't have edit privileges and this is the only thing that would warrant an edit, I'd rather not spend a suggested edit on it, to avoid taking reviewers' precious time.