Found it, dated April 10, 1968. It's a tri-fold brochure, unfolded size is 10-3/16 inches square. I'll have to fire up my big scanner if the laptop that runs it will still boot up. Printed on dark orange cardboard, might be tricky to get a clear background on the scan.
Other price lists I found:
Sound Reinforcement Systems, June 22, 1971
Amplifier Price List, July 1, 1972
Sound Reinforcement Systems, July 1, 1972
New Product Price List Supplement, February 16, 1972 Concert Lead/Bass/Slave, Coliseum 880
U.S. Suggested Retail Price Information, July 1, 1983 includes letter to dealers about price increases.