I don't believe that the HBC clip is correct. No one makes a correct repop one.
There should be "wings" on the outside, so that when you put the holding legs into the hole, you can squeeze the wings with a pair of pliers and it spreads out the legs to make it stay put. The HBC clip has legs, but no wings.
On the HBC repro (and every other repo available) you have to have a second pair of hands inside the car to spread out the legs. They may be functional, but are not correct.
Check out post #33 in this thread.
http://www.camaros.org/forum/index.php?topic=9775.30
Although the pic shows one that was bead blasted and zinc plated. I am not sure of the correct plating.
IIRC, I have one correct on on my car and on repop one.