I'm not sure what bit you mean, I have the classic 8 hole boots and the shape is the same from my perspective?
There are differences as i went Matte finish for the Solovairs and obviously the stiching is a different colour (smooth sided sole too) but i'm more concerned about the quality/fit/longevity of my boots than the Docs aethetic anyway.
Yeah, the iconic yellow stitching on Docs is likely trademarked, Solovairs are grey stitching.