Those little posts that the clips attach to are somewhat problematic anyway. It seems a body guy needs to sweep the panels with a long board to get things flat and straight, and those clips really interfere with that process. But being down low on the sill, that would not be the problem that those little posts cause higher up on the body. When the trim attaches anywhere but the sill area and there is body work to be done, I have my body/paint guy take the little posts off and rivet the clips for the side trim on to the panel. That way I get nice body work. So if you can get the clips, that is great, but if not, it is not the end of the world either to have the clips riveted on. But introducing a hole in the lower sill for a rivet can cause some rust issues later down the road. So if yours is a show car that doesn't get into the rain or snow much, then you are good either way probably. If it is a driver, I would look for the trim clips a little more. Murray Park might have some used ones that could work - you might contact him.
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