I've never seen a stop pin in a Case traditional folder. As mentioned, the kick should take care of that.
I have a few dozen Case folders (mostly 1990s - 2014 or so), and don't recall seeing any significant issues with blade edge contacting the backspring on closing. That said, if one is in the habit of letting the blades snap shut from full-open or nearly so, no edge is safe. Snapping shut HARD allows the backspring to swing past it's normal design limits when the kick impacts it HARD, which then allows the blade edge to sink lower into the well than is normal. I have one or two $400+ custom folders that aren't even safe from such treatment.
If you deliberately squeeze a blade into the handle after it's fully closed, you can see how the kick will force the backspring to deflect further outward than it ordinarily should and, in your grip, you might feel the grinding of the blade's edge on the backspring when you do it. That shows how the damage can be done, even on a well-designed knife, if the closing force is excessive. I sometimes allow a blade to snap shut from near-closed, maybe the last 15° of travel; all my Case folders can handle that without issue.
It's inevitable that a few bad ones will come out, from any maker of Traditional knives. But at least with the Case folders I have, it's not often enough to make me worry about it. And if it does, Case's warranty repair will take care of it anyway, if you send it back to them. I've never had to send one back yet.