Home style molding fasteners made from wire coat hangers.....
Some time ago I needed clips/ fasteners for my Lincoln. There was nothing to be found.The usual suspects wanted a pretty penny for such a rare part. Of course they did not have enough to complete the job anyway.
So looking at the retaining clips for the hood trim I developed my own clips for the rocker moldings.


In fact the Edsel Restoration and Preservation Group posted a few photos of what they needed for their vehicles. Using a wire coat hanger a piece of 2 x 4 and some large finishing nails you can fabricate a fixture do make your own
The clips will attach as shown below
You will need to fabricate a few samples for correct fitment. Make your fixture and then mass produce them...