No I did not! I said to verify proper operation! When a reg was brought in with a specific complaint. After tear down and rebuild, I would dive that reg(on a separate tank) to make sure that the complaint was rectified. For it is only in the water that you are 100% sure of the fix.
To answer the other question, No there is no organization to certify technicians. The only "oversight" is through the controls the individual manufacturers have in place.