Rag and Bone is one wash, IIRC. I thought that some of the Earnest Sewns were as well. Actually, if you look at their site, Nudie is going to have the Straight Sven in something called "One Wash" for the fall season.
I'd ahve to say that 'one wash' in their case is a bogus name. Saw teh pics. There is definite processing on the legs. 'the naked truth' is exposed as LIES... but seriously I'd expect Nudie to at least be AUTHENTIC when naming something like that. The dry and selvage models are accurately named. EDIT: just realized maybe it's supposed to be like a worn pair of raws after their first wash