Enthusiasts of the golden age of the British motor industry owe a great debt to British Motor Heritage, Ltd - the visionary firm that rescued a significant amount of tooling and assembly jigs used to manufacture the body panels of the cars we love. There can't be many nicely restored or renovated British Leyland - era cars on the road without at least a few BMH panels on them. My MGB has a number of BMH and aftermarket panels and there is a real difference in both fit and price. Believe me, the extra cost pays off in assembly.
I've seen MGB fenders up close during removal, refitting and preparation for paint but I had no idea that they are made up from 15 separate components. This video from BMH details the assembly process from the pressed steel parts. It is fascinating.