It might not be unusual, but it is not right. There is no reason for such protrusion and it can be cut back to be the same as the Colt. It is simply a matter of people who think "spec" is a dirty word trying to get the customer to accept the idea that what is wrong is right. There is no reason a punch or other tool should be needed to install the slide stop.
I also note that their tunnel is too short; more of the "we don't need no steenking specs" attitude.