Absolutely correct Jim, 3850's tender was actually first paired with a Star but at some point received a new set of frames and a fully welded tank, triggers broom springs to mind. The drawing I used is dated 1931.
I'm currently doing a Churchward tender in 3D and trying to work out whats what is a bloody minefield. The one I'm portraying is from the later lot A79-80, similar to that behind 3850. I don't have the correct drawings for the axleboxes yet so I'm having to make do with what I have in my library (can't beat good old GWR standardisation) for now.