SQ Quadrophonic System Matrix / Runout: Q2LA.9170 (Label - side A, in parentheses) Matrix / Runout: 12587Q-A (Label - side B, in parentheses) Matrix / Runout: Q2LA.9170 - 1 (Runout, side A) Matrix / Runout: 12587Q A-1 (Runout, side B) Other: 7510 PL (Printer's date stamp / code)