Franco ... my answer here is specific to the use case where you search for a part on PartQuest and you find available (and "download") a SamacSys-partner-provided footprint. These footprints are IPC 7351B compliant. That said, the content provider used 7351B as a guide ... they incorporated some of the "C" spec where they can. They also use manufacturer recommendations as well as recommendations from PCB manufacturers to understand the best specification.
Because the standard is a superset of various standards, there is no certification to cover SamacSys footprints