(a)International classification system. Section 6.1 of this chapter sets forth the international system of classification for goods and services, which applies for all statutory purposes to: (1) Applications filed in the Office on or after September 1, 1973, and resulting registrations; and (2) Registrations resulting from applications filed on or before August 31, 1973, that have been amended to adopt international classification pursuant to § 2.85(e)(3) . (b)Prior United States classification system