Chrome Moulding -- Where can I find plastic rivets?

Sedanman said
Can you measure the clips top/bottom and side/side? I found a bag of trim clips the other day in one of my boxes and I'm pretty sure it's for upper side trim.

Side to side, it measures ~22.5mm (almost 9/10 of one inch). Top to bottom, ~16.8mm (almost 2/3 of one inch).