ISO 17025 is applicable to all testing and calibration laboratories. Depending on the type of legal metrology activity, Legal Metrology Bodies could be accreditation under ISO 17020 if they are am Inspection Body, ISO 17024 if a Certification body and or ISO 17025 as a calibration laboratory.
As Legal Metrology is mandated by Legal Metrology Acts specific to a particular country, there may be other requirements that they need to meet in addition to 17025.
As a Legal Metrology Entity we are involve in both inspection and testing of measuring instruments to ensure compliance with Technical Regulations or Metrology Act. In that case which standards would be most applicable, the 17025 or 17025.