If the
request came in the mail, rather than phone or email, it is most likely
legitimate. There should be a phone # and address that can be verified at the
DOR website (http://www.dor.state.nc.us/).
The letter
should also explain why they are asking for this documentation. The usual
reason is that the withholding you show on line Line 20 of form D-400 does not match the info they received from
the payer sources. Since you don’t have a W-2; they most likely want to see a
1099-R, with an amount in box
12 that justifies the amount on Line 20 of form D-400
