The RRC also required a valid SS# by the original due date of the return ... you cannot amend for a SS# recieved later :
Q C4. Social Security Number Requirement: Do I need to have an SSN to claim the credit? (added January 13, 2022)
A4. Generally, yes. One eligibility requirement for the 2021 Recovery Rebate Credit is that you must have a valid SSN or
claim a dependent who has a valid SSN or Adoption Taxpayer Identification Number issued by the IRS.
A valid SSN for the 2021 Recovery Rebate Credit is one that is issued by the Social Security Administration by the duedate of your 2021 tax return (including an extension if you requested the extension by the due date).
https://www.irs.gov/pub/taxpros/fs-2022-27.pdf
