49 CFR § 173.462 - Preparation of specimens for testing.
(a) Each specimen (i.e., sample, prototype or scale model) must be examined before testing to identify and record faults or damage, including:
(1) Divergence from the specifications or drawings;
(2) Defects in construction;
(3) Corrosion or other deterioration; and
(4) Distortion of features.
(d) The external features of the specimen must be clearly identified so that reference may be made to any part of it.