No duns numbers can be described in any TS certificate.
Do you mean associate with IATF database?
You can only input a single Duns Number in the IATF database when you are a supplier to GM . The IATF database is linked with GM portal so that the certificate validity will be shown on GM portal.
If you are not a supplier to GM, I think Duns number has nothing to do with the TS certification.