AWS Codes and Specifications detail minimum requirements to be followed in the absence of over-riding Specifications. By this I mean that a large amount of latitude is given to the "Engineer" or "Technical Authority", in which they may choose to adapt or change any code requirement, in any way they see fit, as long as they are willing to assume responsibility for their decisions, and such decisions are agreed to between contract parties in writing (Referencing Document) prior to being adopted.
In your case, a "Referencing Document" could be a written Inspection and Testing plan that details the qualification process that has been approved by the "Engineer". Typically, this document would then be submitted to the Customer for rejection/approval.
When Customer approval is not at all practical, say for instance you're selling multiple products to different Customers without contract documents, then the Manufacturer needs to clearly understand the liabilities involved when claiming Code compliance. In this case, the Manufacturer's internal engineering specification and/or inspection & testing plan is the referencing document.

Tim