If you're referring to the time period late 70s, early 80s, when the Dep't. selected for large hatchery summer runs, and the return rates were high and resulted in fishable numbers of fish from late May onward, then no. The natural peak return is July, following spring runoff which peaks in May and June.

The data I had going back to the beginnings of the program in the 60s showed Skamania summer runs always peaking in July. The reason for the early fish was because the tails of the bell curve for timing, with the much larger run sizes, indicated substantial numbers of fish both early and late.