Original 1980s lower GM side moldings were sold by the individual PN#. Each PN# was a seperate location on the vehicle and all the wheel opening trim had that 50 degree cut at and angle and the ends were factory sealed. The original GM trim had metal clips with a single pin that aligned with those small holes, it aided in installation and alignment on the assembly lines. I guess as an added bonus it did help those sharp, angled cuts from lifting away from the body. The individual PN# has been long phased out of GM inventory. Pieces of them can still be found time to time online though. I just bought original left front fender and right rear beside Silverado peel and sticks last year.
Now in your case. Use a small plastic push-pin there under the aftermarket, new peel and stick molding, or maybe add the 2000s GM "mark of excellence" square to hide it (without trim). This chrome "GM" square came in large and small sizes too.
