The IEC 60061 series uses a numbering system in which the part, the sheet and the amendment level are all encoded in the reference. That structure exists so that a gauge can be identified unambiguously in a purchase order, a calibration certificate and a test report, and it fails whenever any of the three uses a different form of the reference.
A lab buys gauges citing a sheet reference without the amendment letter. A revision is published, the supplier ships to the current amendment, and the internal documents of the lab still specify the old one. Months later an auditor compares the certificate to the drawing and finds a dimensional difference of a few hundredths of a millimetre, which is enough to invalidate every result produced with that gauge.
Keep a gauge register that records, for each item: the full sheet reference with amendment, the serial number, the supplier, the date received, the calibration history and the measured wear. Review the standard for amendments on a fixed cycle, and map any change to the affected gauges before the next audit rather than after.
If a revised sheet changes a dimension, old gauges do not become compliant by relabelling. They either remain valid for the old requirement, which is only useful if a contract still cites it, or they are retired. Recording which is which prevents both a false claim of compliance and unnecessary scrapping.
