You're right Perun, the stop notches aren't usual.
Some of this 38SA have "stop notches" without any chamfer and others have some, but when they have some, it's only on the right side and not on both.
Why some have and others do not, I do not know.
On this one, they're original on both side and make the revolving of the cylinder very easy and in the same time the cylinder haven't any play when it's blocked.
It works really perfect.
Why this one has two chamfer, I do not know.
W&S