The L prefix would indicate 1968. Conn bought Best Manufacturing in Nogales, Arizona in 1968, but they were still making saxophones in Elkhart, Indiana up until 1969, when they moved production to Nogales. They were made in Nogales until 1972, when they started making them in Mexico. They were made in Mexico up until around the early 80's after Daniel Henkin bought the company from MacMillan in 1980.