For an angler judging whether the fishing is worth the drive, the stocking record is the fishing report. Wilson Creek is a put-and-take angling fishery, stocked with catchable game fish: 8 recorded releases totalling 691,500 fish (Kokanee, Westslope (Yellowstone) Cutthroat Trout, Rainbow Trout), last stocked 1955-01-01.
Stocking appears to have wound down after 1955. Confirm whether it is still topped up or now fishes as a residual, wild population. The chart below shows the full release history.