Does anyone have any definitive information on this style of bumper bar/bow? I've read it was/is a genuine Porsche part, that it is an Amco bar (that may or may not have been available through Porsche as an option), and that it wasn't Porsche or Amco but another unknown aftermarket brand. They definitely seem to be period correct at minimum and I've seen a few very stock appearing early cars with them, making me think they were indeed available from Porsche one way or another. Any insight?