I'm pretty sure they do. I called and ordered parts recently and they had a kettle lid available. I didn't need one but they had them. The price might be prohibitive thought.
I'm trying to keep it cheap, and I now suspect that the bowl from a kettle is what they use to make the wsm lid. It makes sense from a manufacturers point of view to have to fabricate as few unique parts as possible.
A wsm has been in my list of things to get for years, now I can't believe that I used a cheap offset smoker for years. I didn't have to add fuel for twelve hours when I did the brisket, simply an amazing smoker.