See Darts for Billboard articles about the introduction of this new-style cabinet to the pinball industry. According to multiple lists compiled by Steve Kordek of the games he designed, this is the first pinball machine that he designed at Williams, and his second game for them. His first game was a rifle game, Space Glider, in 1960. The manufacturer's original playfield drawing (not shown here) is stamped ORIGINAL, dated Aug 30, 1960 and signed SFK. On it, the name "Tri-Score" is crossed out and the hyphenated name "Bo-Bo" appears above it. The manufacturer's Tool Room copy of this drawing (also not shown here) is stamped MASTER, drawn 9/27/60, completed 10/31/60.