IMO, it is way more important that it is there and functions than if it is factory installed unless of course you are into concourse judging. I've never been too concerned about correctness since most of us add our own finger print anyway such as electronic ignition, different wheels, bigger carb etc. I make my own grounds using braided tinned conductor and crimped lugs. Simply because it is easier to recognize what it is and what it's job is. You can't have too many grounds but it is important that the ones you do have are clean and function properly. The biggest cause of electrical issues in our old iron is bad grounds and bad connections.