A useful distinction
A manual or label can be useful only if it belongs to the correct item. Similar products may have different revisions or instructions. Keeping identifiers connected avoids transferring one product’s information to another by appearance alone.
Put it into practice
Create a private index linking item, identifier and document. Preserve the original information and add your notes separately. If the connection cannot be confirmed, mark it uncertain rather than treating a plausible-looking document as proof of the item’s characteristics.