The trews that I have are made of a tartan fabric with the legs having only an inner seam. Similar to a traditional kilt, the top sits higher on the waist. When visiting historic sites in Scotland I have seen the staff frequently wearing bifurcated garments of a tartan material, but the legs have seams visible on the outer side. The upper part is usually covered by a jacket, so I don't know how it fits. Would these be called trews or tartan trousers? Perhaps my question is, what makes a true trews?