Don't know the part numbers...I do have a picture of what they look like
I made some clips out of aluminum that work perfect. Or if you are too lazy, just drill some new holes in the sides and fender lips (if you still have fender lips).
There aren't really clips for the under part of the car. They are things like this _|---|_ that are riveted to the plastic that are used to screw into the car underneath but I didn't use those at all and my skirts are not going anywhere without those utilized.