Well, perhaps there is some mixed truth behind your "friend's" theory. As previous posts have pointed out, there is no way JZD could have ever signed every car built. However, if you remove the headliners, you do find a lot of scribble up on those doors! I removed all of my headliners 2 weeks ago so I can recover them this winter. Looking at the inside of my door I find a TON of marker writings, but nothing I can really make out. All I recognize is a date and my VIN number. Many owners have reported finding strange writing on the insides of the stainless panels in thier D's These can, and have been found on every panel on the car. I was hoping to find some on my doors and/or front fenders, but my car turned up pretty clean. I am guessing this is where that person may have gotten confused, or is just completely blowing you off and just happened to stumble onto a "half-truth". Jim Reeve -6960 Minnesota