I just got home from a Car show and cruise today. I pointed this bulge out to Jeff (71340Rt) and showed him , on his car, how one of his fenders had the bulge and the other one didn't. He said one of his fenders had been replaced. He took some good pics of his bulge fender and my non-bulge fender, showing the difference. When he uploads them, you'll see the big difference in the fenders.
The big money part comes when these guys that have to have NOS, buy NOS. The AMD and Goodmarks, don't seem to have the bulge, but I haven't seen any up close yet.