No, Form 843 doesn't apply to income tax. If the amendment has to do with a bad debt/worthless security, you have 7 years to claim a refund.
You could attempt to send a letter, ensuring you mention you agree to allow them to extend the statute of limitations to assess tax. See: Exceptions to the 3-year/2-year expiration dates There is no guarantee this will be successful, because it is past the 3 years from the original due date that entitles you to the claim.
