Yes, every Federal agency as defined in § 102-192.35 must have an agency mail manager. Agencies that are not “large agencies” as defined in § 102-192.35 may not need a full-time person in this position.
Code of Federal Regulations
Note to § 102-192.120
:
GSA will post the names and official contact information for all large agency mail managers on its web site located at www.gsa.gov/mailpolicy.