[Vasu]

I think it depends on context. If it's a small office where most people know each other even an "Oops, there was a small mistake in the previous email, here's the correct version" is fine. For something like an organization-wide email saying sorry or "we apologize for the mistake" is normal.

All in all I don't think "sorry" is saying too much. It's a pretty formal way for a small apology. For bigger mess-ups things like "I/we sincerely apologize" and wording like that comes into play.