Just to answers Bruce's question, I have no idea who made them, i am at least number 3 on the purchasing chain. All the NOS Porsche pieces I have are marked with a factory label, these have no sign of glue residue.
So I have no idea who originally manufactured these. I do know the stamping was of pretty high quality as all the bed radii are smooth, and with out pucker. So who ever did them, either knew what they where doing with dies and stamping. Or someone spent a lot of time with a smoothing the marks out from a sloppy dies etc....
Sorry I can not be more help with the origin of the panels.