Screw diameter is exactly the same for C mount and CS mount.
It only differs from the back flange (the distance from the end of the lens to the image sensor).
CS mount is shorter by 5 mm.
Depending on the camera, 5 mm thick ring (C mount ring) may be attached to the tip to make C mount.
Therefore, if you remove C mount ring, it becomes CS mount.
This is image of C mount.
remove the c mount ring.
it will be cs mount.