The earliest code I have is the 1980 D1.1. They weren't really referred to as WPS at that time. The code just made a statement that joint welding procedures that conform in all respects to the pertinent provisions of Section 2, Design of Welded Connections; Section 3 Workmanship; Section 4, Technique; Section 8, New Buildings; Section 9, Design of New Bridges; or Section 10, Design of New Tubular Structures shall be deemed prequalified and are exempt from tests or qualifcations. There were forms in an appendix that could be duplicated for documentation.