Huh, I was pretty sure that it was out while I was in high school so before 1986, but I guess that must have been some other adult video game paving the way for LSL.
Maybe you were thinking of Softporn Adventure from 1981. It's a text adventure game by Sierra (at the time they were called On-Line Systems), and Leisure Suit Larry 1 is a graphical adaption of it. Source Wikipedia.
