The deadline in North Carolina to submit those 1040s is April 18th. This is because the law gives a three-year window to claim the refunds. According to a WCNC article the IRS estimates the average amount of money owed to individuals is $813. That's a good chuck of change I wouldn't want to go to waste.
Also, be aware that if you didn't file a return in 2019 you may also receive an Earned Income Tax Credit. This could be worth up to $6,431 if you meet the income requirements.
If the IRS owes you money and you still need to file the 1040s, 1040-As and 1040-EZs for 2018 can be found here.
