Examined a P9 Covert last weekend at a gun show. The slide stop definitely didn't stick out past the slide as much as it did on my very early P9, but it did extend past the flat of the slide.
The dealer was reluctant to let me strip it, and considering why I wanted to, I can't blame him. Peering under the slide stop blade as best I could, it did appear to have the slide stop detent spring still retained by that tiny, thin rectangular chip of plastic. Couldn't tell if it was welded to the plastic of the frame like mine was, or retained by a screw.
The blob of JB Weld plugging the hole in mine still looks like crap, but it's also still there doing it's job of keeping dirt out after maybe 400 rounds, and the pin I used (another slide stop from a K9 with most of the blade ground off leaving a thin "head" or flange) still fits fine and stays in place just fine.
May rig something to retain it more positively than simple friction, but not until it bothers me a lot more than it does now. Plus my P9 is about as slim as it can be now.
Pat
Pat