There is an interesting thread in which these issues are addressed:
Thoughts: From QS-9000 (now IATF 16949) :1998
188.8.131.52 Final Product Audit
The supplier shall conduct audits of packaged final product to verify conformance to all specified requirements (e.g. product, packaging, labeling) at an appropriate frequency.
NOTE: This activity, also known as a dock audit , is based upon sampling and is generally performed after final inspection but prior to shipment. Where customer PPM requirements are met, the frequency of Final Product Audits may be reduced.
Product Audit - A Brief Review
Product audits are most commonly done by a company on its supplier. In some product audits dimensional, electrical or other measurements may be taken. Test results may be reviewed.
Internal audits do not typically include product audits in and of themselves. More typically you will be reviewing the a product audit performed by someone as a function of auditing the Dock Audit Procedure.
QS-9000 (now IATF 16949) does have a Dock Audit requirement. See the Notes below.
ISO 19011 - Quality and Environmental Management Systems Auditing Forum Discussions