Durant sidemount locks?

I am at a loss to know what the side mount locks look like for a Durant. To be specific, they would be for a 1928 D75 Durant with side mounts and the 5 lug wire wheels. A casting is riveted to the plate on the side mount that has a center hole with an internal spline 1.0" deep and beyond that a 1/2-13 threaded blind hole. I am looking for a set of locks to fit this model. Perhaps other Durant models with the side mounts would have the same locks. A photo of the locking mechanism would be a start. Thanks