There should be a sticker on the top of the fender with the VIN number on it. If it doesn't have that or has a BMW sticker with a big R on it then it was replaced.
CarFax doesn't show that my hood was replaced (fan blade caught the rad hose due to a failed engine mount and sent the blades into the hood ruining it), or that my rear bumper & trunk was replaced. But they all were, and at least there wasn't any structural damage and what was done was done properly. My detailer is very good, and if he didn't take his paint thickness meter to my car he'd never been able to tell that parts had be re-sprayed. He was impressed with the work done on my car.
Anyways, was just saying that CarFax can certainly say that a car is original even if it's had damage of any sort repaired.
Cosmos Black/Black 1995 540iA M-Sport
BMW Individual Exclusive Edition, 1 of 65 total, 9/25/95 Build