Thanks! This is my first openscad design, so there are probably things I could improve. From using this for a couple days, I do intend to support the main barrel of the lock in some way, since it rattles on bumpy terrain. Haven't come up with a good solution for that yet.
Edit - The rattle was the lock body against the shackle. I fix this now by sliding the rubber gasket that came with the lock against the lock body.