I think it would be safe assume that there were sockeye in Lake Washington historically, given the presence of Kokanee in the system and the availability of excellent habitat suitable to support rubust populations there. Many less optimal Puget Sound systems still have remnant populations or at least were known to have them. The White River has regular returns of a small number of adult sockeye. I have seen them in snorkel surveys near the Clearwater confluence. McCallister Creek had a decent and sustinable population of sockeye at the McCallister springs pond until they were deliberately extirpated by WDF to address presumed municipal water quality concerns. Kitsap Lake had a fairly big run until it was also intentionally extirpated. Skokomish tributaries, Elwha at Lake Sutherland, any number of streams with a lake and suitable habitat had them. It is safe to assume that historically, systems with suitable accessible habitat all supported sockeye to some degree.