49 CFR § 551.60
When must the Designation by Foreign Manufacturer be signed?
November 18, 2020
(a) The foreign manufacturer must sign the Designation by Foreign Manufacturer on or before the date that the agent signs the Acceptance by Agent. It is not possible for an individual or entity to accept a designation as agent until on or after the date on which a foreign manufacturer makes the designation.
(b) If the Designation by Foreign Manufacturer is dated after the Acceptance by Agent, NHTSA will deem the designation insufficient under this subpart and reject the submission.