I can't tell you exactly, but my driver side on my 55.2 chevy is aftermarket and my passenger side is original. The differences I see is that the original has thicker metal, it is heavier and doesn't wobble when I pick it up (obviously separated from the truck). The original has a loose support on the inside of the fender where it bolts to the upper radiator support. The repo has it welded in. You know where the front edge of the hood lines up with the fender? Well, the repo one has the metal overlapping while the original is formed. Now if someone fills over this (like I plan to) you will not be able to see it. I hit the side of the repo with my four finger tips and it vibrates more than the original. So, have a confused you more?
