Add the URLs to the US Government Documents--they are available every month.
Marcus Jun commented
The United States Government Publications Office (GPO) catalogs bibliographic records and provides purl's for electronic government documents (monographs, serials and integrating resources...).
There exists a CZ collection: US Government Documents but this only includes a selective list of journals. There seem to be a few other gov doc collections in the CZ but they don't have portfolios.
Does Exlibris have plans to reach out to GPO to provide a gov docs collection in the CZ? It seems like there would be many Federal Depository Library Program (FDLP) members and other libraries (who subscribe to Marcive's Documents without Shelves) who would be interested in subscribing to and managing this collection in the CZ rather than importing records monthly into Alma.