Speaking from experience working at West Point in NY...there is no licensing necessary. If you plan on doing work in a facility like that make sure you read the specs. The government will have engineers assigned to the project to make sure that all specs are met.
At first, we thought it would be a nightmare, but in the end, the engineers are the one's taking care of the inspections and QC. Having them around all the time turned out to be great because we could discuss an installation prior to it being performed. Therefore, the work was always the way they wanted it and compliant.