I've noticed a new sort of enterprise in the last couple of years. Reproduction of vintage Porsche signs, not only the enamel metal signs professionaly aged but also illuminated signs.
It's quite simple thanks to current technology: You take a worthless old sign, keep the original frame and lighting system, print a new front. Done. You have now a $$$$ sign!
One of the funniest signs is this one inspired to an italian small hard plastic signs "Ricambi Originali" from early 80's ( see pics) . Unfortunately the maker decided to add an english description which is totally wrong as italian Porsche signs never had an english text. Buyers beware!