Until recently, kids didn’t have social security numbers. Now required to claim them as a dependent. Not required in the 60s and 70s.
Even if it was the 70’s or 80’s, whenever he got his ssn- he was required to show a birth certificate.
He needed an ssn and birth certificate to get his US passport to travel to Pakistan in 1981.
Presumably his assigned ssn, whenever he obtained it, would be coded based on place of birth shown in his birth certificate. Can’t imagine why it wouldn’t be