Official findings and reports; presumption of authority to issue or execute.

For the purposes of this law, any finding, report, or record, or duly certified copy thereof, purporting to have been signed by such an officer or employee of the United States as is described above, shall prima facie be deemed to have been signed and issued by such an officer or employee pursuant to law, and the person signing same shall prima facie be deemed to have acted within the scope of the person’s authority. If a copy purports to have been certified by a person authorized by law to certify the same, such certified copy shall be prima facie evidence of the person’s authority so to certify.