Talking about "what procedures require" is keeping Quality Management in the 20th century. Today's auditors should be asking about what's effective - of management.
In the case of the issue being discussed in this thread, the overwhelming majority of organizations have no procedures, documented or otherwise, related to “filling all fields on shop tags”. What they do is perpetuating tribal knowledge. As a XXI century auditor, one should think context, risk and as Andy said, effectiveness.
Context for example, should this shop be in the nuclear industry supply chain, the practice of missing data in fields on the tag would be a MAJOR issue. Apparently they are in the automotive supply chain, where the risks are not as high.
Risks. What are the risks for missing data on the tag? Ask the downstream internal customer at the plant. Is there a potential for the parts to be mishandled if the empty fields in the tag are not filled? Is there any evidence of quality escapes, product returns, low quality yields, etc due to blank fields on the tags? If not, move along to (hopefully) more relevant issues.
Until the conformity assessment practices are synchronized with “new generation” management system standards, Auditorsaurus Rex will create havoc in the swamp.