It doesn't matter that you didn't redeem them. The money was available to you anytime you wanted to take it, so it was income that you received. Think of it as being like interest on a bank account. When the interest is credited to your account it's taxable income to you, even if you leave the money in the account.
Whether you should amend your tax return depends on how much the income or the additional tax is. If it's very small, don't bother amending. There is no firm or official rule about how much is "very small."
