I received a 1099-R form from a previous employer after my federal and state taxes were filed and accepted. It was for a small distribution from a pretax account that was part of a profit sharing plan I had forgotten about. The distribution was rolled over into a qualified retirement account (in this case a traditional 401k). There was no tax withheld and the taxable amount listed on the 1099 is $0.00. Given this information, my refund will be unchanged. Do I still need to file an amended return for my taxes and include the few hundred dollars from this rollover distribution?
You're supposed to file a 1040X (amended return) and include the missing information about the 1099-R, even though there is no additional tax due. It's a straightforward form and not too much of a hassle. If this will stress you even a little, take the 15-20 minutes to file the 1040X.
You could also just wait -- there's a chance you'll get a letter from the IRS in a few months asking you to act or not act on the information. They could just say, "We noticed and you don't have to do anything."
If it were me, I'd just wait. A Google search on "1040x 1099-r rollover" yields some similar stories with no definitive answer, other than "yes, you should, but if it were me I wouldn't bother."