Hard to Find Original Porsche CUD. Key Ring for Pre-1973 Porsche models. It is 50 years old so it does not look new. CUD stamp has worn off mostly but if you know your CUD's you know it is the real deal. The item "Pre-1973 Porsche CUD 911 356 Key Ring Fob Chain Vintage Rare Original" is in sale since Thursday, July 30, 2020.This item is in the category "eBay Motors\Parts & Accessories\Apparel & Merchandise\Car & Truck\Key Chains". The seller is "ozbey904" and is located in Houston, Texas. This item can be shipped worldwide.