USGC485 said:Your ssn number will remain unchanged, but only restriction "Authorized to work with INS ... " or something like that should be removed after your gc approval.
Otherwise, If they think you are still on visa authorization or ead authorization while you are permanent resident, the govt would stop putting money in your ssn account for retirement or until death if your authorization is expired with H1 expiry date or EAD expiry date.