The part you approve in prototyping should be the part you receive in series. That only happens if the process behind it does not change.
Prototype parts prove the design; pre-series parts prove the process and the inspection plan; series production repeats both. We keep them on the same machines, tooling and metrology so nothing is re-learned between stages.
A prototype made by a shortcut can pass and still mislead: the design is validated but the process is not. Building the production route from the first part avoids the classic surprise where a design that worked in prototyping will not hold in series.
First article inspection for the new or revised part, dimensional reports, EN 10204 3.1 material certificates and batch traceability, so acceptance criteria are agreed on paper before volume starts.