To me, placing the spare tire on the driver's side never made any sense. When you have a flat, you have stand in the traffic lane and remove a spare, further endangering your life! The "curb side" mount makes a lot more sense for sure.
I think that the Metalman uses the stock fender and then with the aid of a template, he cuts the fender oval out, flips the metal over, welds it back in place and viola!, you have a side mount spare fender. You can always send your fender to him and have him do the conversion for you. That's what he does!
Here's his webpage:
Wheelwright Restorations Home Page