LW-6 / LW-4 lacquers are later-numbered cuts from within the original release run, so original-era rather than first. Billboard had BS 2938 among the top-selling LPs by January 1977.
First record played on the new setup where the spatial separation registered on its own — voice, backing vocals and instruments each in a distinct place. Rasp lives in the upper midrange, which the JBL’s two-way design covers on a single driver with no crossover through the vocal range.